It was always planned for us to use the WiFi network to get them online. We do have trunking and spare network ports in class, but I doubt we have the ports available on the switches, especially in areas where we have PC suites in the school. So it would be quite a cost undertaking to do that in every school across our local authority estate.
I'll look into your idea of MAC address though as we do use NPS/Radius for the setup. I feel like I've tried everything at this point so one more thing won't hurt 🤣
It looks like I'll be able to get a meeting with a Smart representative from the UK on Thursday (their email support seems to be on the west coast of America/Canada so when i email them during the day, if they reply, it tends to be 9pm when I am no longer at work, so it slows things down.