In my experience the council websites are the best place to look. Also make sure you get the local free paper, where I live it's the news shopper, usually any local school jobs turn up in that. If you're going to be moving closer to the edge of london, rather than central then also search the local authority sites for the surrounding counties as there might be something a bit further out but still in travelling distance. The job market is the same here as I imagine it is everywhere.....pretty tough. Most schools are laying off staff rather than taking on new ones but jobs do come up if you look long enough and hard enough. Not sure about agency work. I've never thought of it for TA'ing really because none of the schools I know use supply TA's but it might be worth a try. Give it a google and see what comes up.