I have cut my bash mounts off before using a grinder hacksaw and file what you do is get a grinder grind the weld down as much as posible till you think its getting close to the frame then take the hacksaw and cut into were you think the mount starts and as soon as you think your close to the mount and you have done this all the way around the weld and the opisite side to get some mole grips clamp it to the mount and give it a sharp pull the mount will come off and you file up the welds jobs a good one
regards Ryan