Welcome @NeilM 
Your background in bio research/programming sounds cool, have fun messing with the API! If you want to automate some pot deposits though people tend to use IFTTT since Monzo has integration with it 
In regards to private messaging I think you only unlock that after being on the forums posting a while. While you’re waiting for @simonb to respond, if you haven’t seen already there is a topic here about Monzo COps which has lots of people discussing their experience with the application process.
Then there is their job vacancies page
Hope all this helps!