You have to twist the white lever to the right (so it is pointing upwards) - this is now unlocked and then underneath the board (as you look up into the footwell, you have to lie on your back for this) on the left of the board there is a black clip thing that you have to press in to release the board and allow it to drop down.
Found out all the above after MUCH fiddling about grrr....
Kev and his trusted accomplice Mandy :), October 2012
