My brother had a large collection of models like those. When he died we sold some very easily (but for far less than they had cost him!). The majority proved quite difficult to sell and eventually they went to an automobilia auction where they were sold in groups of 2 or 3 per lot, probably to dealers, for comparatively low prices.

The ones that had sold quickly and for better prices were either people's dream bikes & cars, or were exactly the same colour scheme & spec as a real one they owned. Anything else didn't attract many buyers.