Pull the drawer out as far as you can, then look underneath. You'll see under the middle trough there's a sort of 'tongue' that runs the length of it. Just inside the machine, aligned with the tongue, is a retainer. Put something thin and flat (e.g. a fork!) inside between the tongue and the retainer and push the retainer down. Pull the drawer out over the top of it and hey presto.... It took us years to work it out. And now we're buying a new machine!
Alix, June 2008