It's actually quite straightforward. The easiest way to import the car is to put it in a 20' shipping container (SeaCan). For UK the car needs to be delivered to either Toronto or Montreal. There are a number of shippers and freight forwarding companies that can do this for you. I recommend First Air Ltd., who also do surface shipping. I'll forward details if you are interested (incidentally First Air ship all the ALMS cars over to the European races and back).
The freight costs will be around $2200 Canadian - I presume the car is worth it - because you are going to have some additional costs when it is landed. They include import duty (on the freight costs), car tax (based on it's value, engine size and fuel consumption) DOT type approval and PVA test and documentation. Depending on the type of car, there will be some lighting and emmissions modifications to take care of prior to then forking out to the DVLA for all the UK paperwork to be raised. I helped a friend import a 2000 Corvette from Florida. The whole deal (not including the cost of the car, which valued at GBP26,000) ended up costing him around 5K.
As long as the numbers stack-up, then that's all that is required.
I am a self-confessed American car nut so I'd say go for it - on the assumption that you can't put your hands on a similar car that is already in UK, for similar money to what this exercise will cost you.
Let me know if you need First Air's details - good luck.
