Well,decided to check my motor over today ready for the laning trip in a couple of weeks....removed the rear wheel to check the brakes which made me swear !!
The outside pad had worn and slipped through the caliper,it then came to rest on the hub part of the disc and decided to wear a 3mm deep groove in the disc. All it would taken was a decent emergency stop or a lengthy application at speed for it rip apart basically....So...if you hear a little grinding noise coming from your brakes, DO NOT shrug it off as a stone stuck in your pad...HAVE A LOOK !