After a lot of work I've managed to get Yuri's revenge working between me and my wife over the net with XWIS. It took a bit but we managed.
However one of our friends cannot join our games or they crash.
On the screen where it shows players names with a red dot beside them before the game loads my friend has a grey dot that never lights up.
After about 7 seconds we all get booted to the lobby.
Myself and my partner are running Windows 10 while our friend is still running Windows 7.
If anybody has any ideas as to how to fix this please let me know, though I don't hold out a great deal of hope as the forum seems rather dead.