Oh, I'm actively doing this at the moment. FreeAgent grabs my transactions from Wise already, and then I give it [Claude Code, in fact] a folder of PDFs to attach to my invoices, including figuring out VAT, and it's uploading what it found using the FreeAgent API. My accountant hasn't complained yet, and it seems considerably more accurate than when my wife was doing it.

Quiet plug for https://github.com/pjlsergeant/byre which I use for all my little projects like this.