I did finally get this resolved...
I un-pinned the shortcut from my task bar, then deleted the shortcut from my desktop, and the one from my NAV programs group in the Start menu. Then I created a new shortcut on my desktop directly from the actual executable in the programs folder of my PC. That one was working properly, and showing the correct icon. I then pinned that new shortcut to my task bar, and copied the new desktop shortcut to the NAV programs group in my Start menu. Now it's all good!
Thanks for your efforts to be helpful - much appreciated.