Thanks for this thread lads.

I noticed a bit of free play the other day when doing my chain tension. I was going to check the cush drive etc.

Happily i do a lot of mountain biking so have dozen of inner tubes ideal for this job.

Top stuff.

I found the additional rubber had broken down after a few thousand miles, I made up some aluminium shims and have replaced the extra rubber with these, seems to be working well so far.