I am also a relocated Brit and travel back "home" 4 times a year or more. I always rent a car (stick) and not infrequently the cost of the car is more than the flight. It's not just the base cost, on top of that you have mandatory taxes plus of course the fuel. You can save some money if you pay for the car with a credit card that gives you CDW. Also, the flyertalk boards have some useful discount codes for the big name rental companies. Looking at my most recent rental agreement I paid £242 (approx $484) for 15 days rental (Ford Focus) and that was with a £100 discount. Personally I wouldn't go much bigger than that: although I understand dgwright99's point about the MPV, depending on where you are, you may find them a pain to park as english parking spaces are on the small size. As other have said Point A to Point B can look a short distance but may take quite a while, while it is absolutely pointless to have a car in London.