You don't pay orangewheels a penny.
They have deals with certain dealers and they advertise the price the dealers will sell the cars for. I guess they then get some money from the dealer for introducing you.
It's the first time I've tried this so I was a bit unsure like you, but you do all your deal with the Nissan main dealer. No need for haggling as you know the price, you pay your deposit to the dealer. Haven't had any confirmation, but I made sure the number calling me was the garage in question. The deposit has gone out against the garage, so I'm confident it's all legitimate.
The car I'm getting was in the UK unregistered so I ordered it Monday and I should get it next week hopefully, can't wait.
The dealer is in Knaresborough and I'm in Kettering. A couple of hours drive. I love the blue although I know it's not to some peoples tastes!
If you want to wait until I get it, I can let you know if it all goes ok