Going to London for 5 days and wanted to get a car rental for 1 day to see Stonehenge and surrounding sites. There will be 4 of us so a rental car seems to be the best bet (vs. public transport or an expensive tour). The problem I'm facing is that most car rental places have limited hours on Sat. and are closed on Sun. I think weekend days would be the best time to make a drive out there. Is there any car rental facility where I can rent a car for 24 hours on the weekend? Any other suggestions? Would I hit a lot of traffic if I made the drive on Fri?