The only place I've really used is the Office for National Statistics stuff, but it depends what exactly you're after. If you're lucky they've done an analysis that's exactly what you need. But doesn't always work out - they did an analysis in 1991 that was perrfect for the justification for my research, but they haven't repeated since, and I've been criticised for using such old data in my research, but what can you do if they don't provide what you need?!