This brief report won't add much to what has been written above, but might serve to reinforce the impressions recorded by previous guests: this hotel isn't up to MGallery standard and doesn't have much to recommend it.
We wouldn't normally have booked a stay here, given the comments in this thread. So why did we? Because we were booking a single London night at rather short notice and everything was expensive. If a night at one of our usual Mercures or Novotels was going to cost £300, we thought, why not try something new and more luxurious?
Except that this property is not luxurious. Platinum brought us an upgrade from "superior" to "deluxe" but the room was still tiny and lacked what I would consider to be basic amenities in a hotel of this category, such as slippers and flannels (washcloths). When I say the room was "tiny", I mean around 20 m² -- but without the charm of a small Paris room or the clever use of space typically found in Japan.
The miniature safe was not large enough for a baby iPad, let alone a laptop or an A4 folder. The TV looked impressive, but all the channels we could find were decidedly low-def. There was no welcome amenity. The room was 'scented' by diffuser sticks that I found faintly repellent.
Positive: The bed was comfortable and we received a (handwritten) drinks voucher without having to ask.