In another thread, I promised a review of the inexpensive hotel we chose for before and after our RS London tour. We selected the Kensington Gardens Hotel, 9 Kensington Gardens Square, in Bayswater. The guidebook describes it as "pleasant and slightly scuffed," and that may be a fair assessment. The room was fine - bigger than the one in our much more expensive tour hotel (myHotel Chelsea), with en suite bathroom. The room and public areas were spotlessly clean, and the room had big windows that open onto Kensington Gardens Square (NOT Kensington Gardens), a small neighborhood park. The area is very quiet, day and night. A good breakfast is served in the Phoenix Hotel, next door to the KG. Both hotels have friendly, hardworking staff (mostly young Polish girls, it seems.) The rate we paid was 89 GBP per night - a bargain. The downside - which may be a deal-breaker for some: no lift. We were on the fourth floor, (what we would call the fifth floor,) and we were certainly glad we packed light :-) Rooms are available on lower floors, if you request them.
The neighborhood is a major plus. We were only about a block away from Queensway Rd, bustling with shops and restaurants in all price ranges. There is also a nice multi-story mall just at the corner of Queensway, a block from the hotel. Plenty of ATMs as well. Everything you might want or need is available. (I even found a Catholic Church on Queensway.) The Bayswater tube station is about 5-7 minutes walk from the hotel, and it's a short walk south to Kensington Gardens and Hyde Park.
In short, we loved the hotel, the location, the breakfast, and the price. We would definitely stay there again, and can recommend the hotel whole-heartedly, as long as you can handle the stairs.