i used a pair of pliars on the shaft between the caliper halfs, worked for me, if that doesnt work, drill it and re-tap it

the one that goes between the caliper halves that hold the pads in place with the split pin at one end

stick a torque end in it using a hammer and then turn it round using a spanner or your hand it works for me

well it was well and truly stuck today so left it soaking over night hopefully better tomora tryed pliers and i couldnt get it to move i am not that weak either lol thanks for the tips hopefully sort it tomora i will keep u guys up to date

don't know if this would work, but find a pair of those clamping pliers (cant remember the proper name) and with all your effort but that on the end and twist.. that will either shatter it (at which point you know that it wasn't moving no matter what or it'll come out

edit.. molegrips!! thats the one

Two suggestions for you.

1) Use an easyout. Basically this is a reverse thread that you screw into a hole in the stuck bolt, as it tightens it unscrews the bolt.

2) Take you caliper apart thus exposing a large section of bolt which you can clamp in a vice and rotate the caliper half around. This will require a full blead though.

Jay. Have you tried cutting a groove in to the bolt head, the right size for a flat head screwdriver and trying to get i t un-done that way. i did that with one of my disc bolts, that was well n truly seized.

Also, try and file away at the sides of the head, so that you colt get a spanner around it. I don't quite know which bolt you mean, so my ideas might no be possible.
Good luck.  Ben