Thanks for the advice with this - I have just come off the phone to Engine Centre in Southall, feeling initially pleased with what seemed a very reasonable quote for an engine remanufacture, complete with 5 year, 60,000 mile guarantee. On reflection the salesperson did seem overenthusiastic which always sets alarm bells ringing. Needless to say after checking this site and some reports on the RAC forum, I will not be using their services.

I've learnt a couple of valuable lessons today - if something's too good to be true it probably is and oil makes engines work better!

Thanks!