Use last minute.com secret hotels. Cut and paste the hotel description into google and often you can get the hotel name. If not no problem, have used a number of times and always good value.
You bid for a hotel in a certain area of a certain star rating for certain night(s). So you can, say, got for Mayfair 4* and above so you know you'll get a good hotel. We've often used it for nights in London and stayed in excellent hotels, including places like the 5* Grosvenor House on Park Lane for a fraction of the price you'd pay elsewhere.
The site Better Bidding, link below, is excellent to help you with the process and helps you be confident of identifying certain hotels or trying to secure certain hotels...
We've stayed at the Great Northern Hotel by St Pancras a couple of times recently. The rooms are small but it's a really nice place. It's a bit pricey but Expedia and Quidco helped. Had dinner in the restaurant last time which wasn't cheap but really really good.
As well as tea/ coffee in your room, each floor has its own 'pantry' with the same plus cakes, biscuits, macaroons, jars of sweets, newspapers. They don't take the piss in terms of what they charge if you use the minibar and they ask you to be honest about what you've had.
One word of warning ... rooms on the top floor have sloping ceilings in places. You might find depending on the layout of your room the person sleeping furthest from the bathroom has to remember this if they get up in the night. If you forget and you're about say 5' 10" you might **** yourself right on the nose and hurt yourself ... a lot!