Thanks for all the replies, I love Monzo by the way just a bit disappointed they couldn’t have been more helpful on the phone at least just confirming that she is using incorrect e-mail address rather than just saying you failed security, end of conversation and leaving her thinking well what do I do?. I do however understand the security concerns here and they can not be too careful.
To confirm, you guys were right it was down to using the wrong e-mail address and appears that she might have two Monzo accounts using two different e-mail addresses which is why we didn’t get a error at the e-mail stage of login in and convinced us that her main e-mail address was the correct one. Not sure what’s going on there.
Anyway back up and running and we didn’t have to make a trip to a actual bank 
Customer services did continue to respond to us via e-mail offering further help so well done and thank you.
