Small, simple box for Tannoy 609 DC driver?

Evening!

I've been given an old pair of Tannoy 609s. The boxes are pretty much trashed tbh, but the drivers and crossovers seem to be just fine. So I'd like to install them in my campervan! Space is obviously at a premium, so large ported boxes aren't possible. What I'm looking for is the compromise between the smallest box possible that will also let them sound halfway decent. Does anyone have any suggestions? Thanks in advance! Richard