Right, I had this 12 years ago with a Seat dealer in Walthamstow that went out of business. I had paid the deposit and three months latter checked how things were doing and the receptionist said we are closing down next week. I had paid the deposit by credit card. What Seat did was to reallocate the order to another Seat dealer and honoured the discount and the deposit. All ended well except in moving the order I reckon I got added to the back of the new dealers queue.
Ideally you need your Seat Order number and then they will look up your order when you contact Seat UK. The dealer has this number, if they have closed their lines and scarped you won't get this. It's possible that the dealer never placed the order with Seat and kept the deposit. That will be a claim on the credit card company if you did it that way dependent on what Seat UK says.
One suspects that the dealer may well have taken a fair few deposits over the weekend if they were still trading. I suppose you could cut your losses make a claim against the credit card company or bank if you paid by card and order another one from another dealer or wait will Seat UK sorts it out. If you paid cash you become a creditor if Seat UK doesn't step in and iron things out, then you get a percentage back. Could be a trip or phone call to Citizen Advice if it's cash payment dependent on what Seat UK say. I think if they have no record of your order and you paid by bank card get your money back that way and proceed with a new dealer. In my case the order had been passed to Seat so logically they had taken their cut of the money.
Given what happened to me I'm a bit worried myself when I pay off the balance that my dealer won't go under in that period the money is clearing and I pick the car up.
As all financial advisers say (I'm not one just a humble management scientist), blah, blah, blah. I did run my own consultancy business for 18 years, I always went proactively after people that owed me money, but they were public bodies. A personal visit can work wonders, least to try for that Seat customer number.