If I understand the situation correctly, Brompton USA dealers are subjected to minimum advertised pricing (MAP) constraints. Selling new bikes for less than MAP would most likely result in termination of the dealer contract. So getting a new Brommie for less than list, at least in the US, ain't gonna happen.

Price match isn't going to do much for you if all the Brompton USA dealers are selling bikes for the same MAP. The only leeway you might find is in accessories for your new Brommie, but I don't know if Brommie accessories are limited by the same MAP. Accessories from other manufacturers might not be limited. The markup on accessories is typically much higher than markup on new bikes, so there's a little more room for leeway in pricing if you buy the bike at the same time.