[Perfectlap]

Check your local UK Porsche magazines like Total911 and Purely Porsche and check to see if perhaps some back issues discuss the IMS swap. Then do some research on the Porsche forums like Rennlist to see if there are members who can vouch for the shop.
These magazines often feature shops that work on on those cars with the steering wheel on the wrong side.

p.s.
I would be hesitant to go to a shop that didn't stock the right kind of IMS bearing.
The IMS swap has become a fairly routine part of clutch replacement.