Miltz, sorry to hear about the import approval for the sierra, but i dont think you will be able to get it in, The cut off date is jan 1989. so all cars (not just cosworths) built after this date are exempt unless you have owned them and lived in the UK for 12 months prior to importing the car.
On a side note i have just come across the damaged escos that was here in WA the guy decided to sell it and i have bought it, going toturn it into a track car, as it can not be road registered.
Pics of it.