Last summer we stayed here... It's right across a tube station and in walking distance (5 - 10 min)to the Camden market.

The rooms were fine, the breakfast was acceptable. It's nothing spectacular or extravagant, but we were super-happy, especially for where it's located!
(If you were going to Brighton I could tell you about a hotel with Sex Pistolsn rooms and Bettie Page suites!)

You won't stay until July 17th, hm? *sigh*

www.camdenlockhotel.co.uk

...the Lord Jim [travelstay.com] hotel (the link points to an intermediate we sometimes used. They have their own website where you can book rooms without having to pay commission, but it's buried beneath all kinds of intermediate booking agencies). It's slap bang in the middle of the Earls Court [streetmap.co.uk] region of Kensington, round the corner from Earls Court tube [tfl.gov.uk] station, and it's affordable for London standards but actually quiet. Walking distance from Kensington Gardens/Hyde Park and Harrods [harrods.com]. What more does one need? ;^)