FreeAgent
UK accounting software built for freelancers and sole traders — invoicing, expenses, Self Assessment support, and MTD-oriented workflows. Especially attractive if your bank offers it free with a business account.
Accounting (UK sole traders)
Bookkeeping suited to UK indie authors trading as sole traders, including MTD-ready options.
2 tools
QuickBooks (UK)
Widely used UK cloud accounting with sole-trader plans aimed at Self Assessment and Making Tax Digital readiness. Compare current Sole Trader vs Simple Start features if you are VAT-registered.