I see that its not possible to exceed the highest resolution in the settings prog for this game, I took a look at the config file and added my own resolution which proved this. My question is what do the other values represent in the config file? There is usually one for windowed mode and I am wondering which it may be as I am happy to play in a window if possible.

Finding info on this game is quite hard as you get bombarded with later versions of the game whenever you search on google.

UPDATE
I found these tools for Paradox games which should help with other titles also...

Unknown Entity

What is the highest (default) resolution of the vanilla game? (IIRC it was 800x640 max?)

I believe that is the max res for EU 1, HOI 1 is 1280x1024.

I have had limited success with the Unknown Entity tools, I tried running HOI 1 in a window as well as the other games in the series using D3D Windower, HOI 1 and Victoria 1 worked fine but EU 1 and CK 1 didn't display properly. So I just installed Oracle VM VirtualBox as its free and I am now running all of the games in the series with no problems, its just not worth the messing about with all the other tools when a VM works best.