I have just fitted a new bracket, new pads and a new disc hoping to fix the problem, and it is still there

It eventually ground about five mm from the bracket and the disc.
This is pic of the new parts after fitting and less than 1km of testing around the block:




What could be causing this? Seized caliper? Bent hub? Wheel bearing??? I am supposed to be racing monday but if I can't fix this I won't be
