It's marvellous what a difference Milo makes..... or in any case, tightening up your dec worm!
When I reassembled the mount several weeks back, I think I neglected to make sure the worm blocks were compressed in along the axis of the worm, and it left a bunch of play. I've also rigged up a swinging weight on the RA axis, which seems to help, but it was a quick bodge up and needs some fine tuning I think.....