The BMC have released a new leaflet/pdf on belaying and abseiling. The leaflet has been updated to keep up with changes in belay devices. The booklet includes greater emphasis on 'assisted braking devices' such as the Grigri 2 or Eddy; these devices have sometimes incorrectly been referred to as 'auto-locking' - this term is misleading because the devices do not allow you to belay hands free. They merely assist in holding a climber; you should always keep hold of the braking end of the rope.
The leaflet also deals with the importance of matching your belay device with your rope. Many ropes are thinner than ever, and new dry treatments on a rope can make them feel even slicker in a belay device. Download the leaflet from here:
Image from BMC website.