Our other main stop in Dover was Dover Castle (so we managed to hit the National Trust and English Heritage in one day). In addition to an Anglo-Saxon church (lovingly restored in the near present day), which is next to the remains of a Roman lighthouse, on the grounds, the castle itself goes back to William the Conqueror. The Great Tower is kitted out as it would have been in Henry II’s day, when it was a major stop for well to do pilgrims on their way to Canterbury.
There’s also a whole section dedicated to the wartime tunnels used in the second world war, which we did not have time to go into, but sound fascinating.
Here’s the view of the Castle from the Cliffs (aka, notice the changeable weather from when we started our cliff walk and finished it):