On the question where to buy a Brompton for less, the answer is nowhere. Brompton have always had the strictest pricing policy that no shop may sell the product for less than the price set by Brompton. Very early in the company's history, only a few small shops were willing to support them. Then when the product took off, larger chains wanted to offer it at a discount, but they decided that this would put the smaller early supporters at a disadvantage. So now they have the policy that anybody can sell Bromptons but if they are caught selling them at a discount, their license to sell is revoked. Also, no online sales. You can pay for one online but you have to go and pick it up.
So the other side of the coin is, because there is a waiting list, some operators can opt to charge more especially if everyone in a small country does the same thing. You can't buy online so they can't be bypassed.