Don't worry too much about it being a Cat C my VR6 is a Cat C with no service history and we don't have MOTs! Took it to Portsmouth on the rollers and got 187.5bhp was told it was running perfectly!

Is it coming from the wheel itself? On my old 8v it started to squeek after i got it back from having the ignition switch changed then it stopped after about a week!

I would also try and bring the price down!