Thanks to the idea from @HughWells, I made a little AWS Lambda function for uploading the receipts to Monzo from Zevvle, a mobile network I run. It only does the payment items for now, but usage info in the notes and PDF receipts are en-route.
I’ve submitted a correction for the merchant data.
Unfortunately I can’t do it for the other networks, but if you’re looking for something different…
Have a great weekend!