Background
The Organisation
& The Situation
The Organisation
A UK-headquartered
industrial manufacturer and distributor operating
across the UK, Germany, and Australia.
£185M group turnover. 620 employees. Three
acquired entities each running a different legacy ERP with no
integration capability.
The Situation
Following two acquisitions in 2023, the group operated
Dynamics NAV 2016 (UK),
SAP Business One (Germany), and
MYOB (Australia) — three incompatible systems
with no shared data model. Month-end consolidation took
3.5 weeks. 60% of customer orders arrived by
phone and email. NAV 2016 faced end-of-support in October 2026.
The Mandate
Replace all three legacy systems with a single cloud ERP
- Enable online B2B ordering across all three entities
-
Give the CFO a real-time consolidated view of group financials
-
Complete within 18 months — driven by NAV 2016 end-of-support
deadline
My Role — What I Personally Owned
Program Manager · accountable owner
- £3.2M board-approved programme budget
-
Architecture decisions (7 ADRs — cloud, integration, Commerce,
data migration)
- SI selection and fixed-price contract negotiation
- Executive Steering Committee chair
- Go/no-go decision authority at each phase gate
- D365 Centre of Excellence design (post go-live)
Section 1
The Challenge
Month-end close took 3.5 weeks of manual
consolidation across three incompatible systems.
60% of B2B orders taken by phone/email — 4.2 FTE
of manual data entry per week.
Zero real-time inventory visibility across
entities — stock allocated twice, shipments missed.
£1.2M per year in operational inefficiency,
manual workarounds, and duplicate processes.
No cross-entity purchasing leverage —
£2.4M supplier spend managed in 3 silos.
Audit preparation manual and error-prone —
3 instances of material misstatement risk in
prior year.
NAV 2016 loses Microsoft support October 2026 —
zero-day vulnerabilities unpatched.
On-premise server estate 7 years old — £380K
hardware refresh unavoidable by 2027.
3-year cost of inaction estimated at £4.8M — same
as full programme investment, with no benefit.
The Board Conversation
"The business case I presented was not a technology proposal — it
was a risk and cost argument. 'If we do nothing, we spend £4.8M over
three years and end up with three unsupported systems and a hardware
refresh bill. If we invest £3.2M now, we eliminate those costs, save
£1.3M per year from Year 2, and build the platform the business
needs to scale.' The board approved within three weeks."
Section 2
My Approach —
Key Decisions Made
Before a single line of D365 was configured, I made seven architecture
decisions and documented them in a formal Architecture Decision Record
(AIG-IT-ADR-001). These decisions governed every subsequent delivery
choice made by the SI and the internal team.
| Decision Area |
What I Decided |
Why — The Reasoning |
| Cloud strategy |
Azure full cloud — zero on-premise footprint |
Resolves NAV support deadline, eliminates £380K hardware
refresh, unlocks Copilot AI roadmap
|
| Platform selection |
D365 F&O over SAP S/4HANA and Oracle NetSuite |
Native Commerce integration; £680K lower 5-yr TCO vs SAP;
existing Microsoft ecosystem
|
| Integration architecture |
Azure APIM-first — no point-to-point connections permitted
|
Central governance, eliminates integration sprawl — the most
common cause of ERP go-live failure
|
| Commerce deployment |
Headless (CSU + React) not out-of-box Fabrikam store |
B2B UX requirements cannot be met by out-of-box; future-proofs
for additional channels
|
| Data migration |
Phased with two dry runs per entity, not big bang |
Known data quality issues in all 3 legacy systems made big bang
unacceptably risky
|
| Go-live sequencing |
UK-first sequential, not simultaneous multi-entity |
Addresses NAV deadline urgency; lessons from UK reduce Germany
and Australia risk
|
| SI contract |
Fixed-price with named-resource clause |
Budget certainty; prevents bait-and-switch; milestone payments
align SI incentives
|
Section 3
What was Built
& Configured
3.1 Programme Structure
Four go-live events across 18 months, each governed by a formal
phase-gate review requiring my personal sign-off before proceeding.
Phase 1A · Months 1–6
UK Finance & Infrastructure
GL, AP, AR, Fixed Assets, Cash Management + Azure infrastructure +
Power BI foundation
Gate: Finance data quality and ledger configuration reviewed and
approved
Phase 1B · Months 6–12
UK Supply Chain & Commerce
Procurement, Inventory, WMS, Sales + D365 Commerce B2B portal ·
UK Go-Live
Gate: Full end-to-end order cycle tested; three-way match controls
validated
Phase 2 · Months 12–15
Germany
EUR, GoBD compliance, SAP B1 data migration ·
Germany Go-Live
Gate: GoBD compliance verified by legal; German data migration
dry-run results reviewed
Phase 3 · Months 15–18
Australia
AUD, Australian GST, MYOB data migration ·
Australia Go-Live
Gate: Group consolidation validated; full D365 CoE handover
completed
3.2 D365 Configuration — Hands-On Evidence
In addition to owning the programme at governance level, I personally
configured and validated the following in D365 F&O v10.0.46 to
ensure my oversight of the SI's work was technically informed.
| Area |
What was Configured / Validated |
Module |
| Legal entity structure |
Three legal entities (UK/GBP, Germany/EUR, Australia/AUD) with
correct jurisdictional settings
|
Org Admin |
| Financial architecture |
Shared Chart of Accounts (APEX-SHARED), 3 Financial Dimensions
(BusinessUnit, CostCentre, Department), Ledger configuration per
entity
|
General Ledger |
| Procure-to-Pay cycle |
Vendor master, Purchase Order, Product Receipt (GRN), three-way
matched vendor invoice, BACS payment journal — full P2P cycle
validated
|
AP / Procurement |
| Order-to-Cash cycle |
Customer master with credit limit, Sales Order, Picking list,
Packing slip (delivery), Customer invoice — full O2C cycle
validated
|
AR / Sales |
| Financial reporting |
Trial balance review, Period Close workspace navigation, P&L
report generation — confirmed month-end close process
feasibility
|
GL Reporting |
| Integration layer |
Azure APIM gateway configuration, Logic App for order
notification, Service Bus for inventory event processing
|
Azure / D365 |
Governance I Put in Place
Three-Way Matching
Mandatory on all vendor invoices — PO quantity, GRN quantity,
and invoice quantity must reconcile before payment is released.
Tiered PO Approval
Approval workflow by value — under £5K (Procurement Manager),
£5K–25K (Finance Director), above £25K (IT Director / COO).
Credit Limit Controls
Sales orders exceeding a customer's credit limit automatically
held for Finance Director approval — preventing revenue risk
from bad debtors.
Segregation of Duties
Security role design ensuring the person who raises a PO cannot
approve the invoice — a mandatory audit control.
Data Residency
Azure configuration verified to ensure UK data stays in UK Azure
regions, Germany in EU, Australia in APAC — satisfying GDPR and
Australian Privacy Act.
Section 4
Outcomes &
Business Impact
3.5wks → 5d
Month-end close time
60% → 5%
Manual order processing rate
£1.3M
Annual recurring savings
26mo
Full programme payback
| Outcome |
Value Delivered |
How D365 Made It Possible |
| Finance close time reduced from 3.5 weeks to 5 days |
£280K/yr |
Automated intercompany reconciliation; real-time trial balance;
Period Close workspace replacing 14 manual reports
|
| Legacy licence costs eliminated (NAV + SAP B1 + MYOB) |
£220K/yr |
Full decommission on go-live — no parallel running costs beyond
agreed hypercare period
|
| On-premise infrastructure decommissioned |
£95K/yr + £380K avoided |
Azure cloud replaced all on-premise servers; hardware refresh
capital avoided entirely
|
|
B2B online ordering portal live — 60% manual orders eliminated
|
£310K/yr |
D365 Commerce headless portal (CSU + React) integrated to
F&O — orders appear in warehouse queue within 4 minutes of
submission
|
| Group procurement consolidation — single supplier view |
£190K/yr |
Cross-entity purchasing leverage; 8% reduction on £2.4M group
supplier spend in Year 1
|
| Working capital improvement — inventory reduction |
£145K/yr |
Real-time cross-entity inventory visibility eliminated duplicate
stock holding; 10% inventory reduction in Year 1
|
| Total Annual Recurring Benefit |
£1.3M/yr |
26-month full programme payback period |
Section 5
What I Would
Do Differently
Being honest about what I would change is as important as describing
what went well.
1
Data Quality — Start on Day One, Not After Discovery
We underestimated the extent of duplicate vendor records and
non-standard product codes across 15 years of NAV history. A
dedicated data quality sprint in Month 1 — before any D365
configuration — would have saved four weeks in the migration
workstream.
2
Change Management — Involve All Entities Earlier
Involve Germany and Australia stakeholders in UK UAT, not just
their own go-live preparation. Structured observer roles in the
UK UAT phase would have accelerated their readiness and surfaced
localisation questions three months earlier.
3
CoE Timing — Design Earlier, Staff Earlier
I designed the D365 Centre of Excellence post-go-live. In
retrospect it should have been designed in Month 3 and staffed
from Month 9 — so the internal team was owning configuration
decisions by Month 12, not just observing the SI.
Section 6
Supporting
Artefacts
The following documents are available to support this case study and
can be shared on request.
AIG-IT-BC-001
Business Case — Multi-Tower ERP Transformation
£3.2M board submission including investment breakdown, benefit
quantification, ROI summary, and risk register. Approved by CEO
and CFO.
Available on request
AIG-IT-ADR-001
Architecture Decision Record
Seven architecture decisions covering cloud strategy, platform
selection, integration architecture, Commerce model, data
migration, go-live phasing, and SI contract structure.
Available on request
AIG-IT-WB-001
D365 F&O Configuration Workbook
Step-by-step hands-on configuration guide covering legal
entities, chart of accounts, financial dimensions, P2P, O2C, and
month-end close in D365 F&O v10.0.46.
Available on request
AIG-IT-EV-001
D365 Configuration Evidence (Screenshots)
Validated configuration screenshots across all five D365 modules
— legal entities, COA, P2P cycle, O2C cycle, and financial
reporting.
Available on request
Note on Confidentiality: Company name, financial
figures, and personal details have been anonymised for portfolio use.
The architectural approach and delivery model reflect proven practices
from previous implementations. The financial figures have been scaled
to suit the scenario and are intended to be directionally
representative rather than exact client data.