Newbie needing guidance with setup for BT (British Telecom)

[scrappydoo]

I recently decided to ditch my ISP-supplied router and make the move to OPNsense. At the moment, I am using a Zyxel modem in bridge mode connected to my OPNsense device. I have a FTTC British Telecom (BT) package.

I have been trying to get IPv6 working but, coming from the relative simplicity of IPv4, it has been a challenge. I think I am almost there. I pass the IPv6 test. I can also ping and trace route successfully. However, I am experiencing periodic disconnection which I suspect is related to my RA settings (Assisted).

At present, my settings are as follows:

WAN interface is configured PPPoE/DHCPv6, MTU 1492, 56 prefix size. Request prefix and prefix hint are both enabled.
LAN: Static IPv4/Track Interface, WAN as parent, prefix ID is 0. Manual configuration of RA is disabled.

Could anyone who uses BT advise me on the correct DHCPv6 settings, please? I would be most grateful. Thank you.