[///Mik3]

So i've never had the chance to visit any part of Europe so far, however i'll be hopping the pond later this year. The first part of our trip starts out in London where we'll be staying for 2 or 3 nights. There are 5 of us, myself and my parents and my aunt & uncle. I'm wondering if we should consider renting a car. We're flying in to Heathrow.

-Should we rent a car at all?
-If so, should we rent it at the airport? If we do, will we need to return it to the airport, or can we return it to a different location near central london?
-Do most hotels offer Parking
-What about parking at at the sights we go to see.
-Should we maybe consider only renting for one of the 3 days?
-How is public transport?


Things to consider,
-my parents and my aunt & uncle are somewhat older (all ~60). They walk fine, and don't have any problems w/ walking, except that they do of course get tired sooner than i would.
-since it's a group, would things like taking cabs end up being cheaper than taking busses, etc?

any input would be greatly appreciated.