rounded out torx removal

[merlin75]

hi guys
trying to fit a rear hugger on a bmw f800r, got all the bolts out bar one right at the back and tight for access, it seems the bolt is rounded out and my bit just slips
i have read various things to try and was hoping for some real world solutions.
i was thinking of trying to hammer on a socket then turn off as normal? not sure if the socket will grip enough and if i can get room to really hammer it on.
someone said to try cutting a slot in head and turn out with screwdriver....would need to borrow a dremell as cant get hack saw in there!
lots of people say to try next size up of torx or even allen head and remove
stuck on what to try...quick job has turned into a couple of hours now..
so over to you guys what should i try.

[merlin75]

thanks so for
just to clarify its a torx head bolt im trying to remove and access is quite tight/arkward

[merlin75]

so a hex key into a torx head ?? have i got this right