Found the answer:
https://helpforum.sky.com/t5/Broadband/Is-it-possible-to-get-Google-Wifi-mesh-system-to-work-with-Sky-Superfast-2/m-p/3337918#M181066
and then over here:
http://www.skyuser.co.uk/forum/technical-discussion/49773-router-os-sky-3.html#post476368