Definitley lesson learned.

The bolts had a smear of copperslip on them. They hadn't really got properly (corroded) stuck, the metal was so soft just under normal loosening the heads chewed out. I was playing around with the box of the things I have earlier and found you can actually snap the head off the bolt just between the thumb and finger of one hand, it's almost like they were made in 2 parts and just glued together!