Hi Ice
Unfortunately there is no chance of you getting the MAN base with VAA as they only recruit for LHR base (although you will fly from LGW too). There is also a long list of existing crew waiting to go to MAN so it may be a while before you make it back up North!
That said commuting is easy enough from MAN!
There is loads of info on here with regards to what the interview consists of - my advice would be just to go along and be yourself though. Do some research about the Company in general but don't worry about the specifics of the interview itself.
Good luck!
Globe