One of the best ways to see a city (in short time) is to get on a hop-on hop-off bus tour. A open double decker bus takes you around all the important places with live tour guide or audio commentary. We took the Big Bus London tour (started at around 10 am). The famous Buckingham palace change of guards takes place at 11am, so we got off the bus and witnessed this event. I have seen this many other times, it is a 30-45 minute event where new guards march in and old gaurds move out. Most of the times it is boring protocols and "more of the same". There is usually a very huge gathering and it is tough to get a good spot unless you wait in front of the palace long time.
Tip: It is really not worth it, going early to get a good spot it is a waste of time.
Change Big Ben to Second day. You also might want to load up 2nd day with one more place(Trafalgar square).
Also not sure what u have on Day 9. Is it something private special surprise?
Vijay
Hope things are going fine.
masood