2010 2.2 tdci. 60,000miles. Just MOTd last week. I was driving fairly fast today and braking hard down a hill. About half a mile later i braked normal for a corner and after that, felt the brakes binding. Stopped to investigate, hand brake would not pull up and both rear brakes very hot and smoking. Front brakes were fine. Wasn't far from home so crawled back and parked up. Checked about half hour later and all freed up and handbrake working again. Any ideas what to investigate? The fact that both sides bound up was making me think it's something hydraulic rather than just a dodgy pad or something.