As a follow on after a few more hours playing with settings, using 'Settings: IPv6 -> Method: PPPoE -> use same login details as IPv4' I seem to have IPv6 working now, the item I changed, is that for PPPoE > use same login details as IPv4, I originally manually entered my IPv4 login details, which did not work, but when I selected the use same login details as IPv4 PPPoE checkbox, this enabled the router to connect to the Internet etc.
Early days yet, but looks promising, now to test Geo-Filter etc 👍