I have driven in Ireland Germany and Italy. The most valuable bit of information for Americans trying their hand in Left side driving is that whenever you are driving an auto, you should keep the driver's door near the midline of the road. When in Ireland or GB and you make right turns, you are turning across a lane, left turns you are not, but the concept of keeping your door side ( in England, the right side) of the car near the midline makes driving fairly easy. SOme AMericans put a not on the dashboard KEEP LEFT seems to help to remind them for a day or so til you get used to it,

I do not know any rules about turning in any of these countries, but my advice is, be alert, be courtious, don't speed in ENgland, DO NOT under any circumstances, stay in the left lane in Germany someone will run over you. WHen in Italy, remember that the drivers there are very aggressive. Give them their way.   Have a great trip I am getting ready to drive in Croatia and Slovenia in October, so I wlll report what that is like!