Looking at the fiches.....

The entire stack of bearings, including spacers, washers, locknut and top bolt are the same part refs.

Depends on the length of stem and some fiddling with lockstops...

I'm doing this mod to my NC29 at the moment. Just pulled apart the 29 front end and offered up the 35 and it is NOT a straight swap. The 35 stem is too short by around 10mm. There's not enought room to fit the lock nut.

Anyone know any engineering shops in Essex who'd press the stem in and out?

My 29 is from 1991 so an RRL. I don't know if the later years will be different