I've just emailed. Here's part of what I had to say:
The Canterbury Arms plays an important role as a place for music fans to drink before and after concerts at the Brixton Academy. The Brixton Academy regularly attracts thousands of music fans to its concerts and those people need somewhere to go before and after the gigs, and the Canterbury Arms, by being a backstreet pub that’s very close to the Brixton Academy, has served an important role in keeping those people off the streets in Brixton. While there are other pubs in the area that also serve as pre and post gig pubs for the music crowd, there are not enough to cope with the sheer volume of people who come to the concerts, and the Canterbury Arms plays an important role in keeping Brixton tolerable on concert nights. The demolition of the Canterbury Arms would lead to more congestion on the streets on the concert nights, and would have a negative impact for everyone.
I do think its function as a place to go before and after the Academy gigs shouldn't be underestimated. The Academy is Brixton's elephant in the room, in a way - it's huge, it brings thousands and thousands of people into the area on gig nights, and we need a structure in place to deal with those people. There are other pubs but there aren't enough, and on really busy nights the Canterbury opens up the back room as well, and takes 300 people off the streets of Brixton. That has an affect on everyone who lives here. That's just one of many good reasons why it should be saved.