Ooh - ooh! My hubby has solved it while I've been hunting around on the internet looking for the solution to the drawer-locking mechanism. It's a key! Well of course it is! (But I could see no escutcheon-type thingy so thought no more along those lines...) But he did and tried one of our square-headed screwdrivers like a key and Lo! and Behold! when he poked it in the hole I described above and turned it he could lock and unlock the drawers. It does them all at once. Awesome!
I thought I'd let you all know. Some of you might even have one of these cabinets with a locking mechanism like this and be completely unaware it is there. The square keys are hard to get these days so the screwdriver we used was a Number 2 Robinson's screwdriver. Kind regards... Megan