My first driving under British rules was fine as long as I was on narrow roads in Scotland. My first encounter with a round-a-bout was a near disaster, as I (naturally) went around it the wrong way. My wife also tended to drive too far to the left and hit every drain opening on the side of the road. This was some time ago, the one-laners with laybys probably are 4-lane divided highways by now. When I got to the south, roads were crowded and slow; I gave up and went by public transit which was good.