We are in the UK for 4 days. Two in Salisbury to visit Stonehenge and Bath. Two in London to see the various sites. Public transportation from Heathrow to Salisbury and then around Salisbury is very time consuming. I'm considering renting a car, it would be cheaper and easier to travel on our own schedule. How difficult is it to drive and get around? I'm considering returning it when in London and using public transportation then. I'm a little worried about driving on the other side of the road!