Cheapest blanks I've found so far are £510 for
650mm wide 40mm thick tops from thehardwoodfloorstore.co.uk - these
use 40mm wooden stave construction.

I've not fitted worktops before so any advice appreciated.

sounds expensive, unless that is for the whole lot and not lengths ......
also check here;
http://www.clarkswood.com/worktops/worktops.htm

£510 was for two pieces, so a bit cheaper than your suggestion, but
thanks for taking the trouble to respond. I just want to make sure I'm
not missing some bargain supplier that everyone except me knows about.
Anyone else got a favourite supplier. I'm near High Wycombe if anyone
knows one in this neck of the woods.

Cheers



Jon