Drivers depot at Exeter would solve it...?
Spot on as there are currently 2 6-car sets stabled in New Yard.
What happens to the crews of the last Down service of the day (arr 0005) and the first Up service (dep 0510)? Do they stop over or are they taxi'ed to/from Salisbury/Yeovil? Unless, of course, wind-down and start-up prep mean that it is all part of the same shift?