I had a HC post at PJHQ and was given food and accommodation there. They certainly wouldn't of had me travelling 100 miles each way. The HC part of the deal is that you are only employed in the UK (the Homeland - not your f*****g house).
It seems like you have probably fallen foul of some buffoon administrator who doesn't like the TA doing regulars' work. Perhaps I'm being too harsh and should give him the benefit of the doubt - perhaps he just hasn't got a GC(S)E in English and can't understand the regulations to interpret them in a sensible manner.
If they really expect you to travel from home each day watch them back pedal when you start deducting your travelling time from your office hours.