The very name of the city makes wallets around the world groan. London can be a very expensive place to spend time. However there are also lots of events taking place each day that cost nothing. I’m not going to tell you to visit Buckingham Palace and Westminster; that’s what guidebooks are for. Here are some free things to get up to in London that guidebooks often forget. London sightseeing For an iconic London photo opportunity, head to the Changing of the Guard, which takes place at 11.30am (daily in summer, every other day in winter). The Prime Median is the line of longitude defined as 0 degrees. It runs…