Hi, guys. I think this is the place to put this. I've done a search but, as I don't really know what the problem is, and it's really hard to describe, I've not found anything::

The bike wobbles slightly from side to side as I ride along and, also, if I hit overbanding or a ridge that runs parallel to the tyre, the whole bike tilts that way and almost throws me off. It's difficult to trace where it's coming from (front or rear), it's very unnerving and, until it's sorted, the bike's unrideable.

Tyre pressures are fine (30/31), shock settings are equal, the wheel is aligned properly and I've done a check of the nuts and bolts at the rear end but nothing seems amiss (I only checked them by hand).
I'll be doing a thorough check tomorrow but if you can offer any pointers, I'd be most appreciative.

Thanks in advance, Neill