Begin with a reliable opening position.
An integrated model needs opening cash, debt, working capital, fixed assets and equity that reconcile. If the starting balances do not tie together, the forecast can produce misleading cash movements even when individual revenue calculations look reasonable.
Schedule the movements behind the statements.
Receivables connect invoiced revenue with collections. Payables link expenses and payment timing. Asset schedules connect capital spending, depreciation and the balance sheet. Financing schedules separate borrowing, interest and repayments. Each material movement should have an explicit treatment.
Worked example: profitable, but cash has not arrived.
Suppose a new business invoices £100,000 in month one and pays £70,000 of operating costs. Ignoring tax and other items, profit is £30,000. If all customers pay in month two, month-one operating cash movement is negative £70,000 and closing receivables are £100,000. Collection in month two converts that receivable into cash; it does not create a second sale.
Use checks that reveal problems.
A balancing balance sheet is necessary but does not prove the forecast is correct. The scope can include reconciliation checks, cash-flow roll-forwards, debt movements, scenario consistency and investigation of unexpected balances. A review should also examine the logic and evidence behind the assumptions.