During this year one the brakes seemed to rub and on inspection it appeared that it was not releasing fully. This seemed to be caused by the cable sticking, as if this was given a shake then the brakes would fully release. Once the cable was removed it was clear that the cable was not moving freely in the outer casing. However, after lots of WD40, pulling and twisting etc and finally some grease all is well and the brakes now move on and off with great ease.
Useful things are - a good head torch, so you can see what you are doing and an old piece of carpet to lay on !