Ive been working on the atrium question myself. Have an upcomming London stay (June) and trying to decide if we want to return on points (stayed back in Sept on a paid stay).

I do seem to remember Molton Brown in the large dispensers in the shower.

The atrium is not directly addressed online in any reviews that i could find. But i think i put it together.

Check out my review above from Sept 28, 2024 with the floor plan, and then the floor plan that sof_lance posted from Aug 5, 2022.
I was on the 3rd floor while they were on the 1st. Then compare to google maps and you will see the back half of the hotel is shorter than the street front side.

These photos must be the two atriums. The floor plan also matches the room description in indicating the rooms are accessed by stairs.

The atrium pictured on the left is the black stairway and the smaller one on the right is the tea room. Interesting to see that room 120 is inbetween both!

Im lilkey going to roll the dice and book it (gold so may snag upgrade).

I am worried about noise. That hallway was loud in the evening (I believe the bar is downstairs). Hope to get put in something overlooking the tea room.