The lock inside the door has snapped (sounds like Geoffs problem). As it is so old I am wondering if it is worth repairing - I would think spare parts this old would be hard to come by and noone would do it under 2 weeks, possibly longer.
Thankyou.

Meg, November 2009

My door latch died today. It does not seem to be the latch but the intermideate piece of plastic that transfers the push button motion from the front panel to the door latch. TO see remove the filter on top of the wave. You will have access to a single screw above the operator panel. Remove this screw push up from the bottom to remove the panel. The panel is connected by cables. Dont forget to unplug the unit before you do anything. I was then able to push on the latch part that is holding the door closed. I did find that the part that was broken is a piece of plastic. Now all I have to do is find the part number.

Bill Chambers, December 2009