He's still going mate, still got the shop - must be near retirement age now, but I asked him about rebuilding my Dommie 99 gearbox about 3 months ago and he said it would be after Christmas till he got round to it as he was so busy.
He's always got plenty on - recently Peter Williams has announced that he's putting together a run of new bikes and Mick is doing the engines and boxes for these (15 I think), so i wouldn't think he'll be quick.
I rebuilt my Dominator engine last year after the camshaft woodruff key sheared (no damage luckily) I used one of Micks engine rebuild DVD's and it was a pretty easy process really, you're more than welcome to borrow it if you fancy? He also does a gearbox DVD.
I also use the same machine shop that he does for all of my engine work, so they're pretty clued up on Norton stuff - I'll happily drop anything to them if you like.