Hi Dave
I have just imported a 1970s m/c from Italy into UK and there was no vat or duty to pay. HRMC website is pretty good - the form you need is 414 or 415 (if I remember correctly) downloadable from HRMC site.
You'll need to be able to prove that it has come from an EU country and that it has been used in that country and that all relevant taxes were paid although it seemed to me that it was all implicit and that was acceptable.
Hope this is helpful.
Regards, Rob