Accommodation at UoBWatch
Usually you rank your top 6, and then they assign people (in a random order) to their highest ranked accommodation that is still available at that point, so you're likely to get one of your top 6, but it's pure luck if you get your top one. Chamberlain and Battery Park are both massive, so there is a decent chance there would still be space at one of them even if you got unlucky with the random order.
There are a few other big ones, but they're the main two big tower block type ones (although Chamberlain has some smaller blocks too). Battery Park is a bit further away from the uni, but a nice walk directly along the canal to campus/the train station and right next to a massive Sainsbury's, while Chamberlain is on the Vale (so think nice green area, big lake, less traffic noise than in Selly Oak, feels a little safer to walk to in the dark), but it is at the top of a hill which can be absolutely brutal after a long day at uni!