Hi Vince, welcome to the forum. I expect an expert will be along in a bit, but in the meantime I got an advisory on this year's MOT for the same thing, (barely) discernible play in between the shock and the swing arm - double-sided arm in my case. I can't feel the effect while riding, so I've flagged it as something to look for this winter. Post up here when you've investigated/fixed it, I will follow with interest
