We applied for accommodation in june last year, I remember cos I had an exam in the morning, so was later applying for it!
As for where to apply to. Personally, I don't think any of the residences are more social or anything than any of the others. It just depends on who your house / flatmates end up being. Personally, I feel the westwood pod rooms are too small, but that's just personal preference. I thought I wouldn't really like sharing a shower and toilet at the start of the year, but it really hasn't been an issue. I've had to wait for the toilet once or twice, and never had to wait for the shower.
One thing maybe to consider is that if your on an O2 phone contract, apply for westwood. You can barely get signal in quite a lot of the eastwood houses (I have to be leaning out of my window lol), or in woodland court (not sure about Solsbury and Marlborough).