I've sussed it myself - remove the 9 screws from the aluminium backplate, taking care not to cut your fingers on the sharp edges! Unscrew the 2 element retaining screws and unclip the 3 spade connectors and get your glamourous assistant (in my case, my wife) to catch the element before it hits the oven floor.
Refitting is a reversal of the removal process. Your missus may complain of tired arms as she hold the element up to the holes from inside the oven whilst you try to align the holes and screws from the other side - they are pigs to line up.
Nick
November 2012