Priceline Hotel: Need London Bidding Help!

[littledebbie]

Here is my situation. I am going to London May 5-9. I wasn't having any luck with bids for the 4 nights, so I decided to split my bids and bid for May 5th for 1 night and got the Novotel St. Pancras in the Blooms/Marble Arch area for $70 on my first bid. That was about 2 weeks ago. Since then I have been trying to get May 6-9 as a block unsuccesfully. (My husband would like me to get the Novotel St. Pancras for the rest of the stay so we don't have to switch hotels. But I've been getting more desperate, so I have expanded my areas. I have been bidding 4* in the Bloomsbury/Marble Arch, Finsbury/Islington, Westminster, The City/London Bridge, Mayfair/Soho up to $130 unsuccesfully and 5* in Westminster and Mayfair/Soho up to $190. Is there something going on starting the 6th that is affecting hotel prices? Also, does anyone have any suggestions for other areas I should try? I want a reasonable likelihood that I'd get a hotel that is pretty central, a less than 10 minute walk from a tube station, a safe area, and I don't want an area that has been having a crummy 4* coming up a lot for hotel wins. Should I try to split up my bids even more by bidding May 5-8 and May 8-9 separately. I'd hate to be running all over London though. What should I do?!