Fox FM in Oxfordshire (UK) are running a competition to win tickets to the gig in London on Thursday night at the Mean Fiddler, which according to the Fox FM website has a capacity of around 400 people!  They're also giving away copies of the High Times album.

No closing date is given on the site, but the sooner you enter, the better! 

Update: 11 Nov 22:28 GMT: It looks like the competition may well have ended already.  Sorry.