Stayed here recently in the post corona virus / covid era.
My notes :

-At the time of my visit (July 2020) only the top 3 floors (8, 9 and 10) were open and being used for guests.
-I have stayed here in 2019, and can confirm the room this time looked as always, with no noticable differences at all. Nothing seemed to be missing or reduced. There is a "cleanstay" sticker on the door when you enter.
-Staff at reception and the bar all wear face masks. There was only 1 single person at reception the whole time I was there.
-Morning room cleaning has to be reqested each day if you want it, and staff will only do this if you stay out of your room during the cleaning.

-Breakfast is not being served at all. The restaurant was fully closed. You get a small take away bag which has 1 very small orange juice, 1 apple, (1 granola bar ?) and 1 small sweet pastry. There is a machine for coffee and tea. If you have had the extensive breakfast here in the pre virus era, you will be very disappointed in this regard.

-The club lounge is fully CLOSED. There is no alternative offered, except maybe a few drinks vouchers for the bar if you ask.

-The hotel looked very empty when I visited.

-Central London is very eerily quiet and empty like I've never seen it before....but trains run on time, you get a seat everywhere, and there are no long lines or long waiting times anywhere. Many "smaller" (less used) tube / metro stations in central London have been fully closed. Check TFL (Transport for London) website for details.

Beware that many shops, bars, restaurants, supermarkets, fast food outlets, coffee shops, banks, etc in central London have decided to stay fully closed. Check online before you head somewhere to see if it's really open.
Those that are open, may be open only on reduced hours.

Happy to answer any questions.