Saguaros,
Thank you for wanting to have a look.
It's too difficult for me to clone the site, so I have given you access.
I have tried updating all extensions, or unpublishing/publishing them, to find which one may be causing issues, but unfortunately I can't resolve it.
I have a backup, in case things go wrong while you are looking at the site.
I hope it's something simple that I can't see, but you can.
Many thanks for looking into this.