Many grateful thanks for your time and advice, Pert, it is much appreciated.
I managed to debug the code too, albeit eventually. Like you noted the comment syntax but your other suggestions to correct the errors I didn't see and again I am grateful to you for pointing them out. I also agree with you about the documentation or support from Embedded Adventures, in relation to this product - there is none!
I believe the 'backpack module' (PLT1001) I have for the LDP8008 is not working but nonetheless, I wanted to run the LDP-8008 directly from the Arduino itself to produce a very simple LED display message containing just a few words (and not even scrolling!).
Despite scouring the web and other forums for what feels like an eternity, I've been unable to find any working code that can run this LDP-8008 matrix directly from an Arduino, i.e. from a sketch.
In this respect I've completely given up on the matrix from Embedded Adventures and switched to a standard well supported system based on the MAX 7219's.
This is all a shame really as when the LDP-8008 is working (as I have managed running a python script on a Raspberry Pi) it works well. But like I say, documentation and support from Embedded Adventures is next to useless.
So much time wasted on this product, my project is now weeks behind schedule.
Live and learn.
Many thanks again,
M.