Cannot disable Touchpad when mouse is plugged in, missing ELAN tab in mouse properties.

My partner has a relatively new ASUS laptop running Win 10. I am trying to disable her Touchpad when the USB mouse is plugged in because it accidentally moves her cursor around when typing.

When I go into her mouse properties via Control Panel there is no ELAN tab present in which to tick the box to achieve this (I have a much older ASUS notebook and the ELAN tab is present in Mouse Properties and I can tick the Disable box). Googling the problem basically tells me to update the Touchpad driver, or remove and re-install which I have done (even with "remove drivers from machine" ticked), but no method adds the ELAN tab. (The Touchpad works fine, there's just no way to Disable it while a mouse is plugged in).

Any ideas on a way to achieve this?