Four workbooks reviewed · 12 months of data · 18 August 2026
Fennimore Joinery prices its jobs, tracks its stock and calculates its payroll on four spreadsheets. Three of them carry material risk to the accuracy of a number that reaches a decision. One of them is sound.
The margin workbook is the problem. It is not broken in a way anyone would notice: it opens, it recalculates, and every figure in it looks like a figure. Two of the three faults below produce numbers that are the right shape, in the right column, formatted like their neighbours. They have been wrong since the file was copied forward in March.
Somebody typed a result over the formula. Those cells no longer respond when a cost changes, and eight of the eleven were last correct in the 2025 rates. Margin overstated by £3,910 across the twelve months in the file.
The same job number appears on two rows, with the same values, and both are inside the total. Revenue overstated by £18,400 and margin by £6,850. Every report built on this sheet inherits it, including the ones taken to the bank.
Re-keyed each week from the ordering system export, with no link between the two. You put this at about three hours a week. It is also the only workbook nobody else in the business can produce.
Three separate figures, kept separate on purpose. They answer three different questions and they are never added together.
These three are not added together, and that is deliberate. The first is demonstrably wrong in the file today. The second rests on hours you reported. The third has not happened at all. Combining them is how a £16,000 problem gets sold as a £33,000 one, and it is why most audit numbers cannot be checked.
Separately from whether the numbers are right: what happens if one person is not there.
This is the part owners tend to already suspect and have never seen written down.
| Asset | Depends on | If unavailable for two weeks |
|---|---|---|
| margins-master-FINAL-v7 | Your bookkeeper only | Month end cannot be completed; no job-level margin visible |
| stock-control | One employee only | Reordering stops within about five days |
| rates-2026 | You only | Quotes continue to be issued from a file nobody else can check |
| payroll-hours | Your bookkeeper only | Payroll can be run, but overtime would need reconstructing from paper |
Scroll the table sideways to see every column.
No workbook above has a written owner, a note explaining what it does, or a record of what changed and when. That is the cheapest thing on this list to fix, and the one that pays off the day somebody leaves.
Every finding, with the cell reference so you can verify it yourself.
| # | Workbook | Where | Finding | Impact | Basis | Severity |
|---|---|---|---|---|---|---|
| 1 | margins-master-FINAL-v7 | A4:A48 | Seven job numbers duplicated across rows; both copies inside the total | Revenue overstated £18,400; margin £6,850 | Measured | Critical |
| 2 | margins-master-FINAL-v7 | E7, E14, E19… | Eleven hard-typed values inside the margin formula column | Margin overstated £3,910; will not recalculate | Measured | Critical |
| 3 | margins-master-FINAL-v7 | D9, D22, D31, D40 | Four lookups return #N/A; the Rates range moved and was never repointed | Cost missing on four jobs; margin overstated £5,240 | Measured | High |
| 4 | stock-control | whole file | Rebuilt manually each week from the ordering export; no source link | 138 hrs/yr, and one-person dependency | Observed | Critical |
| 5 | rates-2026 | B2:D96 | No input validation and no change log; feeds every quote issued | A wrong rate would price work silently until a job is invoiced | Scenario | High |
| 6 | margins-master-FINAL-v7 | file | Four copies of this workbook in circulation, three of them edited since March | No authoritative version; decisions taken from whichever was open | Scenario | High |
| 7 | payroll-hours | F2:F40 | Overtime entered as free text (“4h”, “4.5”, “half day”) | Silent miscalculation; only caught when somebody queries a payslip | Observed | Medium |
| 8 | All four | – | No documentation, no named owner, no change log on any workbook | Nothing here can be picked up by anyone else without a conversation | Observed | Medium |
Scroll the table sideways to see every column.
Severity. Critical: a wrong number is reaching a decision or a return today. High: likely to produce one, or the business stops if one person is away. Medium: costs time and will eventually cost accuracy.
Ordered by exposure removed per pound spent, not by what is most interesting to build. Every price is fixed and agreed before any work starts.
| # | Action | What it removes | Fee |
|---|---|---|---|
| 1 | Rebuild margins-master with live links to the rates table, input validation, and duplicate detection on the job number | The whole £16,000 of errors found, and stops them returning | £1,200 |
| 2 | Drive stock-control from the ordering system export instead of by hand | 138 hrs/yr and the one-person dependency | £850 |
| 3 | Lock the inputs on rates-2026 and payroll-hours, with validation and a change log | Errors get caught at entry rather than at year end | £600 |
| 4 | Consolidate the four circulating copies into one authoritative file with controlled access | Decisions stop being taken from whichever copy was open | £450 |
| – | Ongoing maintenance, changes and support | Workbooks stay correct as the business changes | £250/mo |
Scroll the table sideways to see every column.
Recommended first step: item 1. It carries the entire measured exposure, it is the fastest to do, and it is about three working days. Nothing else on this list needs to happen for it to be worth doing.
You may also reasonably do none of this. Items 3 and 4 are within reach of anyone confident in Excel, and this report tells you exactly which cells to change. If that is the outcome, the audit has still done its job.
The £300 audit fee is credited in full against any of the work above commissioned within 60 days of the date on this report. It is credited once, against one commission, and it is not conditional on which item you choose.
This audit covers the four workbooks supplied on 14 August 2026. Files not provided are outside its scope, including anything held only in email or on a local machine.
Findings are based on the structure and formula logic of those files as presented. The underlying source data has not been independently verified against your accounting system, your bank, or any third party.
Every financial figure in this report says where it came from, and those labels are not decorative. Measured means a fault was located in your file and the difference computed, and you can check it yourself. Observed means a figure derived from hours you reported, priced at loaded cost; it is only as good as that estimate. Scenario means the cost of one named failure, written as an illustration of exposure. It has not happened, it is not forecast to happen, and it is never added to the measured total.
Time savings are estimated from the current process as you described it. Where a finding did not fit one of the three bases above, it appears in the register with no figure attached rather than with an invented one.
This document is prepared for the named client and describes the files as at the date above. It is not an audit in the statutory sense, it is not financial advice, and it does not constitute a certification of your accounts.