If you remove the front 'skirting board' panel (across the bottom), then pull out the short 'appendix' drain tube. Unplug the drain pipe and drain into a low flat baking tray. (you will get a few tray fulls out).
Then once drained open the front of the pump. Its on the left, and you will see a white plastic thing begging to be unscrewed, and will probably find coins etc. in here.
I've just done this myself, but the machine still wasn't emptying so bought a new pump (Just the motor bit= £28) and it still didn't work (only a dribble in the drain outside), and found the real problem was that the outlet pipe was blocked where it goes through the wall. So I probably didn't need a pump afterall.
If you do need a pump, remove the old one (2 screws and two pipes and 2 wires) by tilting the machine backwards.
Mark Dransfield, June 2009