This is a little different than your typical day in London!  I stayed in Richmond, which is about halfway between downtown London and Heathrow, and I spent the morning wandering around beautiful Richmond Park.  Then, the day I was there, it just happened that they were holding the finals of the Fever Tree (Queen's Club") tennis tournament, which is an important grass court tournament-- one of the main warm up events for Wimbledon.  So I attended that in the early afternoon.  In the late afternoon/evening, I did a bit of typical sightseeing.  Very fun day!