Yes sir the Hotel does exist and know of it, just near some clients of ours.
It does have a phone number I belive and like Rob says unlikely they would advertise in this way surely even though a third party.
Im sure the scammer just use google and like you say get one which is a bit vague on details.
I dont visit london so often now on business but if people need assitance checking out places like this im sure I can try and help.