What the till has to produce
Every sale needs a date, line items with quantities and unit prices, the VAT rate applied, and a total. If your till can export that per transaction, the filing side is an administrative exercise rather than a data-entry one.
The three fields people get wrong
Unit price before VAT instead of inclusive, the wrong VAT rate on zero-rated staples, and a missing buyer PIN on B2B sales. All three are record-keeping errors, not software errors.
Export early, not at deadline
Run the CSV export on the first of the month and reconcile it then. Discovering a mismatch on the filing deadline is the expensive version of the same problem.
Ask your accountant about the route
Certified integrator or manual filing is a question for whoever signs your returns. Do not take a vendor’s word for your obligations — including ours.