Grinding noise in rear end when braking. Noise stops when fully braked but starts up for a short time when I accelerate.

This could be cause by your worn out pads. Some car would have thin metals on the pads that gets exposed when the pad is wearing out. The exposed metal then makes contact with the disk. If the pad is still in good condition you may want to inspect physically the wheel and its assemble for physical wear. It could also be caused by bearings starting to wear out or may just need a grease job.