Thanks for the explanation. Will take a look at it next weekend.
Just to confirm to you all, my rattle was coming from both rear inside break pads ( pads furthest away from the wheel ). They both had a bit of play and rattle loudly even when touched with my finger. As a temporary fix I just knocked a thin peice of tin between the base of the pad and the caliper housing then bent it around so it would not fall out of place whilst still allowing the pad to move back and forth. Rattle has gone away. Will do proper fix on the weekend.