Thanks for that Bill.
Basically it looks like there are 3 types available then.
1. Solid Bronze bush
2. Steel case with pegged bronze inner
3. Steel case with bonded bronze inner
After speaking with a number of dealers who specialise in BSA twins, timing bushes (either type) are available in oversize outside diameters when specifically required. You may have to pay a little more as they are a special but they are available.
If we are only talking about 0 to 0,001" play ie. the hole in the crankcase is 1 thou bigger than the outside diameter of the bush, then the general consensus seems to be that an appropriate Loctite (641, 668 or even 648) would do fine - just a little now...don't go blocking those oil ways !!!
So after all this talking, phone calls and E-mails, that's what I'll do. I'll buy just a normal bush off the shelf, probably a 30 under size, Loctite it in, have the crank ground to clean, then the bush line bored to match.
Thanks for the feedback folks
Lets hope it all works..Bye for now.