Yeah the BT looks like the option... went in to Abtec in Petone and (as luck would have it) they'd just finished putting a single-din with the after market replacement surround into. Which looked fine - and whilst my initial thoughts were to go down that route, I've since realised while I'll gain in the sense of an easy to use digital music player, I'll lose some of the computer stuff, not to mention the non-originality and it's also more cost than a BT solution.
Likely to go BT and then if I win Lotto I'll get a Dynavin lol