I'm new to the forum, and GTD. So I'm getting my tools together, and after much trawling through forums and blogs, I can't find a filing cabinet in the UK with compression plates. I also discover a whole subculture of UK GTD practitioners and students with various workarounds for the problem!
Then, as a result of a refusal to admit defeat, I finally found a manufacturer of filing cabinets based in the UK, Triumph, who also manufacture an old-style compression plate for their foolscap filing cabinet. Here's an online retailer who sells the range at a good price:
And here's Triumph's website:
Great filing cabinets too!