They have maintenance staff based at Neville Hill Depot that maintain the HSTs, and Depot Drivers there too who move HSTs for EMT, Cross Country, and Virgin East Coast around the depot between fuel and inspection roads, the carriage washer, maintenance sheds, and stabling roads. They also move Virgin East Coast 225 sets around as well. They also move coaches in and out of sets with a class 08 shunt engine.
As said above the trains in service for EMT are out in the early morning and back late at night. The mainline drivers for these are based at Derby and the Train Managers and on board staff based at Sheffield.