Hey Marc,
Unfortunately not. As what you are describing is an issue which is not supposed to be happening it is likely something specific on your site stopping it from working.
Looking at the HTML output of my menu on your site, something in your theme or another plugin is completely overwriting the class names of my plugin which is why it is not working.
Can you try disabling all plugins on your site and see if that fixes it. If it does, then you can activate all plugins again one by one until the issue returns, at which point you know the offending plugin.
If disabling all plugins doesn’t fix it then you will need to deactivate your theme and switch to a base WordPress one. If this fixes the issue then you will know that the theme is what is overwriting my classes.
Please let me know your findings.
Peter