Guess the city - part 4

A quick hop over. Guess where we are?? A BIG clue:

This is a very groovy escalator.

A fabulous display in a fabulous old building.

Oh, and we also popped by to see if the Queen was in.

Alas, she was not but we did stop for a scone with jam and cream. Mmmm....

A lovely residence the Queen has.

Yes, that's right, We are in London!!