Hi again,
Spoke to the salesman yesterday and turns out firstly he made a mistake anyway and its around £150 less than he thought. Apparently it falls in the showroom tax band of around £750. He's also offered to pay £150 towards this so i woild have to make up the 150 to 200 pound difference. The problem is they gave me a really good deal on trading in my 350z and so if I cancel and order elsewhere I will lose value on my trade in as it has already been a over a month since I did the deal and I would also have to restart the waiting process if I order a new one from a different garage. I'm still not completely happy about it but I don't think I am going to gain by going elsewhere as I will definitely have to pay the showroom tax then anyway. The salesman even suggessted that he could cancel the deal if the garage felt they weren't making any money on the car...so basically he's making it sound like the contract isn't worth the paper it was written on. I bet if it was the other way round they would be using the contract (which doesn't include any price change clauses btw) to their advantage.