Hi David
The ACOC cannot give out official valuation, as it puts the onus on the club, However if you speak to 428 Registra, Andy Shepherd or Bertie either should give you a realistic valuation, obviously the vehicle needs to be viewed on thoroughly inspected, photographs hide a multitude of mysteries and horrors.
Speak to other owners and check out their insurance value, rember should you have accident the insurance company will only pay out or pay for a agreed value, Skilled craftsmen working in Aluminium is both time consuming and bloody expensive.
Good Luck !!
Keith L Lessiter