I downloaded the Debian package that James kindly provides on Bridgewater-Brunel and set up a server on an Ubuntu VPS. I tried to connect to it using a Windows client running the latest pak128.Britain-Ex pakset, downloaded using the Nightly Updater (which at the time was 11 August). However, there was a mismatch between the paksets. I downloaded
the latest nightly pakset tarball to the server and this matched the Windows version (and was playable after other changes to be posted in other bug reports).
The Debian package contains two versions of the British pakset: Pak128.Britain-Ex (with upper-case P) and pak128.Britain-Ex (with lower-case p). There are minor differences between them (for example, the latter has DOG_WALKER pedestrian paks). Comparing them with the nightly tarball in Krusader showed that both Debian versions had many duplicate files which looked like liveries from before the creation of the current livery system.
So it appears possible that
the script used to create the package is accidentally using an outdated repository.
The Debian package also contains this pakset's .dat and image files. This is a matter of preference rather a bug, but it surprised me that an already large download/unpack was being made larger (the source files are just over a third of the unpacked data).