Hi,
I brought my car back from the US in 1999.
At that time it cost me $2000 in shipping charges. I didn't pay any import tax as this had been our family car for more than 12 months. However if you are buying a car just to bring back here, you will have to pay import duty on top of your shipping. Then you will have to pay for any conversions to make it UK Road worthy for example replace red rear indicators with yellow ones.
Hope this helps.