We are going to rent a car for the day to take a trip out to Stonhenge and Bath. The car rental company suggested that we rent the car from Heathrow to avoid the congestion zone. There are five in my family which means we will probably need different tube passes because we'll have Zone 1 & 2 travelcards? And how long will it take to get out to Heathrow by tube on the weekend? Does this sond feasible or does anyone have a better suggestion? Or should we just try to rent in the city?