Hi Manga,
Thanks so much for your reply =D
The CoH folder had all permissions turned to Read & Write for all users and applied to all sub folders. I also updated my OS to Big Sur and experienced the same issues.
However, after much spelunking through the forums I discovered that another user bypassed this issue using bootcamp which I completely forgot existed.
Yesterday I was able to successfully partition my drive, install the windows client and log on to the game.
It is not the ideal solution but I found a way!
Thank you for all of your help and I will definitely try any new mac launcher builds that come out to see if I can get it running on my main partition.
So appreciative of what you guys do!
All my best =D