I use Intermotor's web site to cross reference stuff like this it states that VAE06 is the correct one for Cosworths .

Also found this

http://www.worldcarparts.co.uk/CarPa...3/Default.aspx

Which would suggest that the 2 part nos are interchangeable

I know that does not help the fault , but should remove the doubt that the ISCV is at fault , rather something else around it .