Thanks all for the replies.
Yeah the fence only wobbles when it's not locked/clamped down, I'd never cut when not locked down
Glad (I think) to hear it's not just mine that has this issue, I normally angle the fence away from the blade when locking it down to ensure there is no pinching. I'll try pulling the fence towards me to straighten it up and also half locking it down.
Will take a look at the tensioning nut and make sure all is good.
I have contacted the manufacturer, but given the fact this seems like it's a "feature" of the saw/fence I doubt anything will come of it.
I think this is the wrong way - you PUSH the fence away from you, into the saw, so that the black 'T' section is firm against the track, as you lock it down. (At least, that's what I do!!)