The short version
Each limited company needs its own records. Selecting a company should select its transactions, bank accounts, receipts, invoices and reports together.
Keep payments with their invoices
If Company A issues an invoice, its payment belongs to Company A. Switching to Company B must not move the income or outstanding amount. The same separation applies to receipt links and category rules.
Review the trial balance before filing
A trial balance needs opening balances and explicit capital, loan and director entries. A difference should remain visible until you reconcile it. Cashbook reports are not statutory accounts or a Corporation Tax calculation.
Check each company’s dates
Companies House supplies accounting and filing dates. A long financial year can cover more than one Corporation Tax accounting period, so check the full rules at https://www.gov.uk/prepare-file-annual-accounts-for-limited-company. SimpleTaxFlow keeps the books and digital pack separate from the filing service. Start with SimpleTaxFlow: £1 + VAT/month for 6 months, then £5 + VAT/month.
Put this into practice
Follow the step-by-step SimpleTaxFlow workflow when you are ready to act.