Right I need to change my rear discs for the mot, and that runs out this week.

The caliper comes off no problem, but it is the 8mm allen bolts on the carier that are stuck.
Some clever dealership has slipped em in the past and not replaced them, my 8mm allen key is new so no scores/wear and it is slipping.
It is in such an akward place I am not sure how to get them out, one idea is to file em down on the outside to get a 15mm / 1/2" drive onto it or a 15mm spanner, but leverage in such a spot is still problamatic.

I really need some input / ideas of how to get these bolts off so I can remove the disc.
Oh and the disc is gona need beating with a hammer to get it off otherwise i'd try slipping it out, but not keen on the idea to loosen it incase with it loose it still wont come off.