I own a 2 br there, so maybe I can provide some information.
I don't think there could be any guest rooms - it has been renovated so that there are only 1 & 2 br units. But some are bigger than others, so I guess it's the luck of the draw as to the size you get. It's still functioning as a hotel, until the sale of all the units is complete.
The decorating is awful. They must have fired the firm that came up with the original design scheme and replaced it with a friend or relative of someone. But management is aware of this and claims to be planning to do something about it.
The restaurant - Le Gavroche - is separately owned but there is access to it through the lobby. It's one of the best in London.
The concierges, Peter and Hayden, are outstanding.