seem to recently developed noise from the rear offside wheel. Im making the assumption that its to do with brake rather than bearings and will get her in to be looked at tues/wed but wondered if anyone any ideas first. First off there is this "whine " sound that comes and goes but disappears when brakes applied gently. Im also getting a screech if I have to brake harder but it doesnt always happen. Also less likely to hear it in the wet. Bit of grit or something possibly? There is more brake dust on that wheel too. Only had its MOT end of Feb and had new pads fitted and was fine afterwards until last week.

does it come and goe around corners? if so could well be a bearing

no, corners are fine and certainly doesnt feel like the estima did when that had a bearing go.

I had a similar problem the my old Astra 1.8i Sport, although a bit more of a rattle than a squeal, which also stopped when brakes applied. 

Turned out it had popped the anti-squeal bracket (or whatever they are called) from the caliper.  A simple metal braket that fits onto the back of the caliper, very cheap (couple of £) and very quick job to replace.  Something worth having a look at, I only noticed it when I compared the noisey one with the other and saw there was something missing.

have look at the disc and see  if it has a scratch ring in it, if has may be a stone or a hard part it the disc pad.

brake pads..

As cem says, it's probably due to brake pad dust buildup especially if the pads were cheap replacements. It could even be a cracked pad. :-/

cheers guys-my gut feeling agrees with the sort of things suggested, just as long as its not too expensive a fix! So hope it is the pad not the bearings!