Yeah, I've driven in England, Scotland and down in the Virgin islands.
I never got very comfortable driving in traffic in larger cities like London and Edinburgh. Making turns in big intersections was particularly bad.
Highway/interstate driving isn't bad, just remember which is the slow lane.
Driving on small rural roads in England and Scotland worried me as well. Many of these roads seem only wide enough for one car. It is on these roads where many foreigners have accidents. Often due to hedges or curves you don't see the on coming car until the last minute and your instinct is to pull to the wrong side of the road. So be careful in this situation.
In Europe I was driving a left handed vehicle so it may have been more uncomfortable for me than most.
Fern