Unless I missed it, if you add a receipt (directly by taking the picture in the Monzo app) to the wrong transaction, it isn’t easy to move it (Android at least). Of course you could screenshot and manipulate that way but a ‘move’ or ‘download’ button would be nice.
No - I’d just send a 1p from another bank and that’s my transaction. 300GB currently costs me £24 a year. It’d be a good saving! Difficult to navigate I do grant you - but very safe!