I crawled out of bed on day 2 of my excursion to London  believing that the cough was getting better and went to book my ticket for a the on bus tour. Although they never seem to run on the schedule they say they do, and one drove past me once while waiting to get on, I have found they are a good way to see a city for a day. The walk on tours are usually open air on the top, they stop at all most of the worthwhile sites to see in a city. Tickets are usually good for 24 or 48 hours depending on which purchased.
It was on the tour that I experienced London’s typical weather of sun, rain, wind, sun, rain wind, etc. Probably not the best thing t do for a nasty cough and developing head cold.
Here are a couple random pics from the top of the bus. 
Tower Bridge

london eye

big ben

the crowds at piccadilly circus

phone booths all over london