The moment a client approves hours, Templio raises your invoice at the charge rate and the contractor's self-bill at the pay rate. No re-keying, no spreadsheet in between, and nothing goes out that HMRC's self-billing rules would reject.
Approval is the trigger. Templio works out the overtime, applies VAT only if you're VAT-registered, and numbers each invoice so a retry can never create a duplicate.
Under VAT Notice 700/62 you can only self-bill a contractor who has agreed to it in writing. Templio collects that agreement and keeps checking it, so a self-bill is never raised on a lapsed or invalid one.
Draft, sent, paid, overdue. Invoices past their due date are marked overdue every morning, and paid status comes back from Xero on its own, or you mark it yourself.
Not every agency runs Xero, and an agency funding its book needs a schedule for the lender. Every export is a CSV laid out for where it's going.
Timesheets in. Approvals done. Both invoices waiting in Xero. Insurance tracked. Margins in view. What's left is the part of the job that makes money.