Booking London attractions

[BumWhisperers]

There seem to be so many different deals when buying tickets and I was hoping I could ask here and see if anyone knows the best value (cheapest) way to buy tickets for the attractions we'd like to see later this summer? It'll be 2 adults (one 18 but no student card) and we dont live in England if that makes a difference for any of them

We'd like to see:

Buckingham Palace
Kensington Palace
Tower Bridge
Tower of London

If anyone is good enough to help, then thank you!!

It might be worth looking at the London Pass:-
https://londonpass.com/en-us
Although the pass doesn't include Buckingham palace unfortunately.

If you are travelling by train at all you could get 2 for 1 for Tower Bridge if you have a qualifying ticket -
https://www.daysoutguide.co.uk/tower-bridge

Thank you, I'll look into these both!