I have noticed before that car salesmen here in Thailand know little to nothing about the product they are selling, for the same salary they work at Lotus or the like.
The Toyota dealer who wouldn't let me test-drive the car was in Thayang, so I drove to another one in Cha-am, where I got the same answer, except that the saleswoman had one of these models herself and was inclined to let me test-drive it.