mcfc11

hi there, i have just purchased new drilled and grooved discs with pads for the front and rear, the front discs went on with no problems but the back has now got me off the road, i removed the piston retaining bolts with no worries but then tried to remove the carrier bolts to change the discs and the 1st bolt rounded off, so i put it all back together and went to my local car shop purchased some m10 x 20 come home started all over again i removed the damaged bolt but the old bolts have a smaller thread and the new bolts will not fit.

so my question is does anybody now where i can get the bolts via the web and be posted as i cant collect due to the car being on axle stands now, its just i dont know what bolts to get as the bolt thread is different from the one i got from the shop any help would ge much appreciated.

i have a my99 uk impreza turbo, with subaru 4 pot calipers on the front and single pot calipers on the rear with 5 Stud Vented discs 294mm x 24mm on the front and 5 Stud Vented discs 266mm x 18mm on the Rear.

thanks in advance steve.