There's a more or less unique photo op coming up - the 100th anniversary of the Royal Air Force on July 10th, which will include a 100-aircraft flypast over central London. There's also going to be a parade at Buckingham Palace but you're unlikely to be able to get near it if you're not present or former RAF personnel.
More details here:
https://www.ianvisit...central-london/
I will have to find a good vantage point for this - I didn't see as much as I would have liked for the Queen's birthday earlier this month, too many tall trees near my house, though I did get this, the Battle of Britain commemorative flight: