http://www.atpfestival.com/events/li...nt=20&view=644
thats your second date, theres black mountain the day before, dont know who they are but ,,,,, you may do.
also, stereolab at koko on 11th.
plenty of gigs constantly in london, especialy round atp time.
i dont live in london and never have so im not sure of any site that lists the good gigs, but there should be one, and there are plenty of londoners on this boards so im sure one of them will know.
you could look here
http://www.drownedinsound.com/
or here
http://www.upsettherhythm.co.uk/