As a slight aside, I used to understand how CHAPS and cheque clearing worked in late 1980s. As a demo i asked gemini.google.com to make some obviously spoof cheques (eg Bank of toytown, Totally Stupid bank)... They refused - looks tike a fraud attempt
So I will abstract the problem and ask for a "mail merge" into a PDF or SVG (scalable vector graphics. Which is probably doable in lots of way.