I have managed to fix this by moving dynamic.css to wp-content/uploads and creating a symlink for dynamic.css in the woopress dir.
I was having issues because it turns out that the windows GIT bash tool can not create symlinks using usual commands (despite selecting the option to create symlinks during GIT app install) and I had to create a linux vm to run the commands to create the symlink in the cloned git repository and push it back up.
I reverted the changes made to functions.php beforehand.
