Thanks guys for all your comments, I hope to nail this at the weekend.

The main reason for removing the belts was just to eliminate the water pump, that was replaced in the summer when the truck was serviced & only from reading this forum did I get the mechanic to replace the pump at the same time as the timing belt 'just-in-case', and you guys were right <img src="/forums/images/graemlins/kewl.gif" alt="" /> the original pump was leaking (just a little).

FrankR
I have read almost all of your posts, and totally in ore of your skills & ability.
I can rule out the AC as a source of my problem, the windows work just fine <img src="/forums/images/graemlins/notooth.gif" alt="" />

Thanks again guys.
SteveN