QuickBooks balances your Plymouth books but can't tell the auditor which costs landed against which export-controlled job
Custom accounting software for a Plymouth marine or defence firm typically costs £35,000 to £95,000 over 3 to 6 months. QuickBooks, Xero, and FreshBooks handle statutory accounts and invoicing well; they struggle with deep subcontract job costing, milestone and retention billing to primes, and tying costs to export-controlled projects the way defence finance requires.
Standard accounting tools think in invoices and ledgers. Defence subcontract finance thinks in jobs, milestones, retentions, and the cost of compliance. QuickBooks can tag a transaction, but it can't easily tell you the true cost of a controlled subcontract once you fold in the engineering time lost to export audits and clearance paperwork, the part this whole city's businesses keep eating as invisible overhead.
Billing to primes is the other strain: milestone payments, retentions held until acceptance, and contract-specific terms that Xero's standard invoicing wasn't built for. So someone maintains a parallel spreadsheet to track what's really owed, and the books and the project reality slowly drift apart.
Why the usual tools struggle in Plymouth
- No real job costing that captures compliance and audit time against controlled subcontracts
- Milestone and retention billing to primes forced into standard invoicing
- A parallel spreadsheet tracking what's really owed, drifting from the books
- Project profitability obscured because compliance overhead is never allocated
What a custom accounting build changes
Custom accounting or finance software treats the subcontract as the unit of profitability, capturing labour, materials, and compliance time against each job, and bills primes the way they actually pay: milestones, retentions, contract terms. It reconciles to your statutory accounts while giving you the project-level truth that QuickBooks can't, so you finally know which controlled work makes money and which only looks like it does.
The features that matter for Plymouth
What we build under accounting in Plymouth
The engagements Plymouth teams bring us most often: accounts payable automation, accounts receivable, general ledger, expense management, custom accounting software and QuickBooks integration.
- You bill primes on milestones and retentions standard tools mangle
- Compliance time is real money you can't currently see in the books
- A shadow spreadsheet tracks true receivables outside your accounts
- You can't trust project profitability because overhead isn't allocated
- Your billing is simple invoices with no job or milestone complexity
- Xero or QuickBooks already gives you the visibility you need
- You have little controlled work to cost separately
- Budget won't support a bespoke finance build yet
Accounting pricing in Plymouth: the real numbers
| Project scope | Typical cost | Timeline |
|---|---|---|
| Job-costing layer over your statutory accounts | £35,000 to £55,000 | 3 to 4 months |
| Added milestone and retention billing for primes | £55,000 to £78,000 | 4 to 5 months |
| Full project-finance platform integrated with ERP | £72,000 to £95,000 | 5 to 6 months |
From kickoff to launch: the schedule
Exactly what you get
You get finance software that tells the truth about a Plymouth defence subcontract: real job costing that includes the compliance and audit time you currently absorb, milestone and retention billing that matches how primes pay, and project profitability you can trust. It reconciles to your statutory accounts and links to your ERP, so the books and the project reality finally agree.
How to choose a developer in Plymouth
Pick a team that understands project and subcontract finance, not just bookkeeping. Ask how they'd capture compliance time against a job, how they'd bill a prime that holds retention, and how they'd reconcile to your statutory accounts. The honest answer is usually to keep Xero or QuickBooks for compliance filing and build the job-costing and billing layer on top.
- True subcontract job costing including the compliance and audit time you currently eat
- Milestone, retention, and contract-term billing built for defence primes
- Project profitability you can trust, with compliance overhead properly allocated
- One source of truth instead of books plus a shadow receivables spreadsheet
- Clean reconciliation to your statutory accounting tool and links to your ERP
- Costs far more upfront than a Xero or QuickBooks subscription
- You'll likely keep a statutory accounting tool alongside it, adding integration
- Accurate job costing demands disciplined time and cost capture from staff
- For simple service billing with no job complexity, off-the-shelf accounting is plenty
- !A vendor who equates job costing with transaction tags; ask how compliance time is captured per job
- !No milestone or retention story; ask how it bills a prime that holds retention
- !Pushing a full statutory replacement; ask why not reconcile to Xero instead
- !No overhead-allocation method; ask how project profitability is calculated
- !Ignoring your ERP; ask how job data flows in without re-keying
If accounting is on the roadmap, warehouse management, field service management, erp usually follow within the year. Budget them as one conversation.
Rohan advises mid-market and enterprise teams on ERP, CRM and custom software, and has led delivery on dozens of business-software builds.
Writes for Digital Heroes, shipping business software for 2,000+ brands across 55+ countries since 2017.
Frequently asked questions
Why isn't QuickBooks or Xero enough for defence subcontracting?
They handle statutory accounts and invoicing well but think in transactions, not jobs. Defence subcontract finance needs job-level costing that includes compliance time, plus milestone and retention billing, which standard tools force into a shadow spreadsheet. Custom software makes the subcontract the unit of profitability.
Do we have to replace our existing accounting tool?
Usually not. The common pattern is to keep Xero or QuickBooks for statutory filing and build a custom job-costing and project-billing layer that reconciles to it. That avoids a risky finance migration while fixing the visibility gap.
How do you capture compliance time as a cost?
By letting staff book export-audit, clearance, and dockyard-paperwork time against the specific subcontract it relates to, so that effort shows up in project profitability instead of vanishing into general overhead. That's the cost Plymouth firms most often miss.
Can it bill primes on milestones and retentions?
Yes. The software models milestone payments, retentions held until acceptance, and prime-specific contract terms, so your receivables match the contract rather than living in a parallel spreadsheet.