Right, took the front right wheel off along with caliper, carrier and disc and had a good visual check and found nothing that would rub. I sprayed some WD40 around the back of the hub, where the ABS ring is too.
Put it all back together and for now the noise has stopped, but I've got an annoying squeak now, so the metal grinding noise has been replaced by a squeak. I really don't know what it is. When I'm back from spain I'm going to get some braided hoses and stick them on the 288 calipers and whack them on, along with the pretty new 288 discs and pads. The hubs that came off the 16v have pretty new bearings so I'll use them too as I think it may be a bearing problem. Also, the hubnut had come loose yet again so I gave that a good tightening again, let's hope it holds together.
As I said, engine speed sensor fault is back, so I'll look more into that. I'll try and do the final bit of playing with the wiring before I buy a new sensor (not sure if the Speed sensor affects fuel economy but it seems to have dropped significantly, about 60 miles to £10 rather than what I used to get, 70-80 miles).