Capttrousers

I was looking to buy a 1999 Impreza turbo wagon. Pretty original except for aftermarket end can. The car has 124000 miles and is for sale at £1700. I rang around a number of places for quotes. With a clean license, no insurance claims in 6 years, but no no claims bonus ( they don't count the 6 years I spent living in the US not claiming there). The cheapest quote I got was from Adrian Flux and that was after I mentioned I was going to join the SOC if that helped the price at all. They offered me coverage for $3900!! That's over twice the value of the car! I literally fell off my chair! Am I missing something? I'm 47 married, have a boring desk job, own my flat but I live in London, so where do they factor in the risk to charge such a high premium ? The smallest dent would result in the car being written off, so it can't be that. I am completely at a loss.