I've had suggestions from knackered radiators to cracked heads - luckily a good fiddle and the haynes manual revealed that all I needed to do was bleed the cooling system - there was a shed load of air trapped which prevented the coolant from reaching the radiator, hence it was getting really hot, expanding and spilling out the top up tank via a poor cap seal.
So if any of you share a coolant drinking problem, then maybe this could be a first check! Hope this is of some help.
And for those who asked, here are pictures of My Van!
I intend to post a little on this board with thoughts, events and random things I find in the haynes manual to try and get this group going again because there seems to be so much knowledge here!!
- k e v -