125-200cc British steel isn't what it used to be

Did you figure out what went wrong? Bolts loose?

it appears so yes, I can't tell for sure but it looks like a bolt came out a few mm, whacked into the caliper, the force of the wheel rotating fowards and the brake disc therefore being stuck in position must have ripped it backwards and up into the 'u'shape in the pictures. I put on a new disc and pads and this time used gran ville thread lock, seems fine now , before I didn't use any sort of glue I just did the bolts up