The Iolanthe B&B. Perhaps not central enough for you but worth a look.Easy to get the tube from Golders Green though. Really excellent reviews.I have just booked for my sister as a gift and I wanted somewhere nice but inexpensive.Fits the bill! Especially as my philosophy is to have as good a time possible on as little money as possible! Have a wonderful time. I am sure you will wherever you stay in "Luverly London."
http://www.iolanthe.co.uk/Tarif.htm

Should add that The Iolanthe it is only 58.00 GBP = 91.8760 USD for a double/twin room with ensuite and only 53.00 GBP = 83.9741 USD shared bathroom.
Kerry

My new fave search for cheap hotels apart from Hostel world and Hostelbookers is budgetplaces.com.I have found some great bargains there.Sorry to keep posting but I keep remembering things to add!
Kerry.

Universities are in session in London in May.

>>>>>priceline bidding can be a real win. we'll see... too early for us to start bidding.

My last several stays in London (Manchester too) have been four-stars on Priceline. The rooms have been huge, immaculate, and whoppingly amazing bargains compared to the moldy broom closets you get in the same price range using standard booking media. Have also enjoyed free upgrades to suites and free giant breakfast buffet thrown in. It is by no means too early to start bidding now (if your plans are firm)! If you get rejected, you can always try again later.