In case anyone is following this, I've run some tests with 3 different machines across the same network, I'll call them:
DESKTOP-PC
LAPTOP
MEDIA-PC
The results:
MEDIA-PC connecting to host DESKTOP-PC: Game starts but with sync error
LAPTOP connecting to host DESKTOP-PC: "Could not connect to...
Might be a bit of a long shot for such an old game, but I figured someone here may be able to help :)
I've managed to get a 2-player LAN game working, however at the start of the game both machines receive a warning message about being possibly out of synchronization. From that point onwards...