Today we visited Buckingham Palace & the Royal Mews. By luck we turned up 30mins before the changing of the guard & the 2 ladies in front of us said here do you want our spots. It was freezing & because Ethan & Riley keep insisting on wearing shorts, there were a few complaints. The kids were impressed at the royal carriages at the Royal Mews & were able to use digital headsets to find out all the info.
We walked towards Big Ben & with more luck stumbled across the horse guards right at the time they were changing. 
We scooted past 10 Downing St, captured a few pics of Big Ben, saw the queue & prices for Westminster Abbey then decided maybe for another day? A quick train trip took us to Bond St where we walked by the Disney store then onto Hamleys Toy Store which the kids absolutely loved. By then we were out of time & all exhausted. Planning for a quieter day tomorrow. Definitely not hard getting these kids to bed at night, they fall asleep in all sorts of places in seconds.