I gave up in the end trying to find the problem, after replacing the aux tensioner and aircon pump So took it to Paul at Motormech this morning.
Phone call 2 hours later, its fixed, you know what it was? The power steering belt! Paul replaced it FOC which is much appreciated, so top marks to Motormech again. He seems to think there is an issue with the belt so took it off, and I assume he'll send it back, its only been on the car 8 months!
Need to get front discs and pads done, and rear brake pipes. Need to sort the tracking now as the inner edges of both my front tyres are bald

Ben
(Finally able to drive it again)