Thanks for the replies guys!
Most people are pretty dubious about Brixton - I guess it's like anywhere else in London and can change from year to year. Only takes one really bad experience to change your mind about an area (@henry: yours sounds pretty nasty). But I think this could've happened anywhere in London, or even where I used to live in Cambridge (@tony: Let us know how Canada turns out ). I guess a guitar on your back makes you a target and I'm obviously all too aware of that now.
In general this area has been great to live in - the people are surprisingly friendly for London, there's a great market, independent food shops and restaurants, and a pretty active music scene - the Windmill, Hootenanny and the Jamm are all worth checking out for a pretty wide range of high quality live music.
Anyway, I'll stop there. Thanks for the messages. I'll make sure to post some pics of the bass up (minus me screaming) once the police give it back to me