You may transfer up to 12GB per term. Anything beyond that costs just .22p per GB. Warning notices are sent when you incur charges, and you can check your bandwidth use online. If you need more than 12GB for your academic work, contact the computing officer.
I've just received my death sentence.
edit: FYI I dl'ed over 500 GB in 3-4 months this spring, just via vod downloads, not even streams.