Motor shows are used to demonstrate new and continuing models, they're not used to buy cars.
Why do some caravanners want to buy their caravan at a show some distance from home, presumably cheaper than their local dealer, and then expect the local dealer to service it and carry out warranty work?
The answer is to just use a show to look, compare and decide but then purchase from one of the local dealers in your area. Unless you live in the middle of nowhere just locate the 3-4 nearest dealers of your chosen model, go round each and negotiate, haggle, bargain.
We Brits are pathetic at bargaining but very experienced at complaining, it should be the other way round!