Yes the 6 monthly visa route was my original plan but now of course he doesn't ever want to go back to Vietnam for the other 6 months!!

There's also (as the lawyer advised) a long term visitors visa which still affords the 6 months out of 12 stay in any calendar year but can be valid for 2, 5,or 10 years to save re-applying every year - but again you have to go home.

We have made contact with some of the Vietnamese community here to try to get some tips but (you've guessed it?) it turns out my BF is the only one of the lot who's here legally