Happened to me tonight and i did what i always do and this time i took a photo, also my locks froze and my door was frozen shut aswell!
- Put in car IN gear
- Place a brick at the rear wheel if needed
- Locate mechanism
- Tap it using something long (screwdriver maybe) and a hammer
This will release the handbrake and its should come loose again, also you have to do the other side aswell.
Its the 90 degree bend piece opposite the bleed nipple that locks the cable. When engaged it will pull AWAY from the nipple and if its frozen, when released it will stay in the same position (locked). You will have to tap it TOWARDS the nipple in the release position.
Takes 5 mins and no waiting around. I cannot stress enough that the car should be in gear and have a brick or two to stop the car rolling!