Womble wrote:
Those look like they are effectively short easy-outs, so they are unlikely to break off, but are also less likely to get a solid grip on the bolt itself. I tried to use something similar on a sheared-off sidestand bolt and got nowhere, but when I drilled it I actually managed to twist the bolt out the back of the hole - you haven't got the advantage of a gap at the back, which is why I was recommending the LH drillbit.
Try heating the area around the bolt with a hot air gun before trying, and give the bolt itself a few taps with a punch before you start, both of which should loosen up the threads.
I do still think that you would be better drilling the bolt (left or right handed drillbit) and then trying to unscrew it using an allen key or torx key before you try stud extractors.
Thanks for the advice, I have just been and got a LH drill bit to try this also. Iv borrowed my mates hot air gun too so fingers crossed it will be out tonight...