It can be a bit of a shock to the system I guess..
OK, OK, so what does this sign mean, then?
(That had Joy & Steve totally stumped)
Anyway, it's dead easy. Look: http://www.eastmead.com/driving_uk.htm
Plus: When I was driving in the US a few months back, someone gave me the tip to always wear my watch on the other hand as a constant reminder to drive on the right. No, left. Er..right.
Englishman.