SOLVED! See below.

I tried to this on Linux and managed to get it to run but no battlefield is displayed in battle, the map and commands are there but the battlefield is black.

Initially trying to run it on wine gets an error for a missing dll. To rectify this I had to extract the files from .exe and by putting the dlls from “__support/sys32” into the main game directory “WARFB” I can get it to run on wine but the battlefield is black, From googling I’ve found a few people had this issue on Windows about a decade ago but there wasn’t any solution.

If anyone has any suggestions I’d love to hear them. I doesn’t run at all with Proton 5.X and in Proton 6.13 it doesn’t resize the screen properly but the battlefield is still blank.

Solved it! I needed to overwrite 2 of the DLLs in sys32 that were already there but not the same, should have tried that sooner rather than many of the other more complex attempts!

What did you use to get the files?

I didn't follow these instructions exactly but they worked for me on Ubuntu 22.04, PlayOnLinux 4.3.4, Wine 6.10-Staging and Windows XP. For me it must be run in windowed mode 800x600 or the display starts glitching and the warband will not advance on the campaign map (meaning the first mission won't start).

This is yet again a situation where I have needed to pay GOG for a game I already own, only to find that the only value they have added is to include the .dlls (at very wrong locations) inside their .exe installer, such that with a third-party tool and the kind help of @aqrit it's possible.

Iirc in 1996 these dll files were difficult at the time. I can't remember if we had the internet at that point to download them or if we passed them round on disk, or if I only ever got it working on one pc and never played it again after our first upgrade. So it is somewhat useful that GOG gathered them all together. And also I read this game was originally 256-colours (which normally I don't know how to work round) so there might have been something done with the artwork assets.

But GOG should bring these games up to a standard not just be content that they work on some Win10 test system. If it doesn't work nicely on Wine it is probably going to have issues on some Windows PCs too.