Thank you Andy. It's all fixed. Version 3 now being displayed.
I certainly did install all the upgrades in the proper order (1, 1B, 2, and 2.5). Been playing on 2.5 for a while now. I just reapplied version 3 again and it worked. I have no explanation for it
Thanks for your quick reply.
PS - I love the game by the way, been playing it since my start on the Commodore 64 way back when...that was when the game was called Panzer Strike.