Country sports is my No1 RFD choice, but in all honesty Martin doesn't have a large selection of springers, so I'm not sure he'd be worth the round trip time for the OP,
Likewise the Gunroom at Ivybridge, few if any springers, but a nice shop.
I've not used Crackshot since they were "Ronnie Sunshines" & I thought them way expensive back then.
If it comes to it Trago Mills sell a few cheap springers as well, but again probably not what the OP is after,
Ladds at Crediton have a few airguns (in the Computer side rather than the RFD side) but again I'm wondering if it's good use of the OP's time, although the drive from Exeter to Blue Fox goes right past their gate, so maybe a 10 min call in.
Never been out to Rifleman at Hambridge so Can't comment on them.