I stayed in this hotel 2 nights in a row, but under 2 bookings, so I experienced 2 different rooms. A single and a twin. We stayed during a heatwave this summer and the first room I stayed in was the single. It was very small, but had everything I needed, including a TV, window and AC. Unfortunately the AC was not working so the room was unbearably hot. The window was also painted shut, so there was no movement of air at all. I did ask at reception for a fan, which was brought up to me. Unfortunately it was a tower fan, which mostly moved around the hot air. That night the only way I could sleep was by dunking a towel in cold water and having it laid on top of me. The bed was comfy though, thank goodness.
The second night I was staying in a twin - the room was much bigger and again, had everything we needed - including a working AC system (yay!). Beds were really comfy and amenities included bottles of water (in both room types) which was a bonus. We checked-in in advance and left our bags as we were going to a festival at Hyde Park all day. When we returned there was a long queue to get room keys and our bags. The staff on the desk (2) were really friendly, even though there were a few grumpy people in the queue before us. They weren't able to give us our bags at the time of getting the keys, so they brought the bags up to our room within 30 minutes. That was a bit of a hassle considering we had been out all day, were exhausted and just wanted to sleep, however, we understood that it was busy.
We got what we paid for - perfect location for the undergrounds and Hyde Park in a beautiful building. Shame about the AC in the first room, especially considering it's a 4-star hotel, but ultimately didn't put a dampner on the weekend.