was me when i got the ******* to move!
I didn't have big enough torx bits and my dad has some of those extractors but i didn't want to use them because:
1. didn't want to drill through and leave crap in the gearbox.
2. hole has to be pretty centered and straight and without taking engine out and clamping it in the pillar drill i wouldn't have got it straight.
it was however one of my last options.
I did try a bigger allen key but couldn't find one exactly the right size only the orignal size and to big.
In the end i cut a groove out of the plug then started the bike up and warmed it up then put ice on the plug, removed the filler cap (in case of any pressure lock) and put a chisel in the groove and after a few hits it moved.
replaced with new plug and fibre washer