Hi David,
Barry's advice is first, go to the New Zealand Meccano site
http://www.nzmeccano.com (yes, very original). Introduce yourself through their forum, ask for what it's worth. In all likelyhood you may find a buyer there (they service ANZ)
Barry says it is a late 70s vintage, and they can go from $600-900 by the cursory look of your pictures.