Buyer beware is the phrase you were looking for, Ian.
On the subject of large ship models Antics have a few cased, full-hull models of the two most iconic British passenger liners of my lifetime, Queen Mary and Queen Elizabeth 2. These models are impressive enough to be the centre piece of any collection of miniature ship models while providing a conversation piece in the public area of a collectors home for the same money that you would pay for a good 1/1250 scale model.