My wife and I had a 30 minute massage followed by a 30 minute facial and can say it was a truly fantastic experience; so relaxing and so well looked after.
From the spa with lovely and clean facilities to the treatments, it was a perfect way to spend a morning and i would recommend to anyone.
Very welcoming and clean - everything you'd expect of a Mayfair hotel. The experience was well-managed as the spa facilities, including sauna, steam room and jacuzzi, were not busy - to the point that it was only me and my partner in the spa by ourselves for at least 30 minutes.
The treatment was an hour long massage (not a facial), but it was great, very relaxing and the masseuse was very skilled.
Also stayed for dinner afterwards, which I would also recommend.