Hi Martyn, I can't think of any solutions off hand, not reaching focus when pulling the drawtube out is something you can do a bit about, but when you don't reach it going in that's a altogether more tricky problem. Maybe if you did post some pics that would provide some ideas...
I went for a walk at lunchtime... it's well over 30deg C, hot and humid ... guess I shouldn't complain
cheers,