Welcome tot he forum always great to see new people.
I saved ?10K on the Trams-Am by purchasing in the states, many things could have gone wrong, but turned out well.
Shipping was $700 back in 2002, The vehicle has to be drivable for the ferry crossing from Jacksonville to Southampton. if it isn't drivable you need a container, quotes at the time were around $1500.
Import Tax, this was 10% of the vehicles value including shipping then whacked VAT on top. So around 30% tax in total. However if the vehicle is over 10 years old you didn't have to pay the 10% tax back then. Also if you have owned the car in the states for more than 6 months then you can get away with tax too.
IVA/SVA testing, this has to be some at a few select garages, I done mine in Southampton. Had to change the way the lights worked, and tyres as they have no 'E' mark on them. The test itself was ?175, and ?60ish for a retest, there are companies that can go the conversions for you. I done mine myself to save reddies.
If the car is registered as a 50's farm vehicles you don't have to do any changed for UK, it just has one rear light, no indicators, and its legal.
What age pick up are you looking for?