I never really intended installing a GUI but gave it a try. For a lot of things it is much easier and I probably am one of those more comfortable with that 🙂
Anyway, I had some help from @phenomlab and basically after removing the plugin I then installed using this method.
npm install git+https://github.com/amargon/nodebb-plugin-discord-notification
As I was told it may not be the best method however it worked and the plugin works fine now. As soon as the GitHub version is merged probably best to move back to 'traditional' install.
Thank you for your reply 🙂