My recommendation, don't do it. You'll have to get some small modifications done to the car, mostly the headlights and getting a fog light added to the rear bumper. Depending on the shop you take your car to this can be done very poorly or in an okay fashion. The real problem is that your steering wheel is on the wrong side of the car in a country where the roads are already not exactly laid out to optimize visibility. Keep in mind also the people in Europe do not view their cars as importantly as people in America do. If someone dings your car or bumps into it when parking, don't expect them to do anything about it. That's not to say they're all sh*t bags, they just don't care as much. So if you really like your car and want it to look perfect, I wouldn't bring it to Europe, personally.
That said, there are plenty of people stationed here who have American spec cars, and they seem to do just fine. I personally am happy to not have to think about whether or not my cars going to be damaged, because we just bought two used cars when we got here. Size is also an important consideration, as you mentioned with parking. You don't need to drive a Smart car to find a parking spot out here, but it helps. There're some people out here who have pick up trucks, and personally I don't how they do it. If you have any other questions about England feel free to shoot me a private message. Or ask here, it doesn't really matter.