May 1st is a normal bank holiday in the UK. London may be busier because of that, May Day is a symboliic time, there may be spring celebrations (morris dancers may be out in force! Espeially around pubs. I recommend this actually, good fun) and there may be protests, but the coronation and extra bank holiday are the following weekend. I wouldn't expect much coronation-induced activity as early as the 1st. Personally, I will use the extra bank holiday to do something useful and enjoy the time off work.