Best off using Ralph Colman Cycles in Taunton I would imagine. Partridges is at the side of the A38 after the end of the M5 past Exeter. Never been in myself, but is meant to be good.
Partridge Cycles really isn't all that great! Staff are unknowledgeable and not helpful, and the stock is overpriced and old (but not quite retro yet!)
Big Peaks at Ashburton is a loads better shop and the staff are loads better as well! It's further for you to travel, another 20 miles / 20 minutes down the A38 but it's worth it!!!
Soanes cycles is 10-15 minutes outside of Honiton. Great staff, lots of old and new stock of parts, not the biggest shop but they are very reasonable and do a great deal on parts/repairs.
I'd recommend them way beyond anyone else in East Devon. Link here:
Thanks for the tips guys. Probably ought to have said: it's for an american friend coming over who's looking to rent or possibly buy a cyclo cross or xc hardtail.
Just went to my local bike shop for first time today and they are very helpful aswell, nice looking shop. They do rentals aswell i think. Its called Exmouth Cycles.