Thanks for the suggestion.
Yes, I disabled the DHCP server on the SH2 and used the DHCP server on the piHole. This works fine for IPv4 but not for IPv6.
The SH2 does not allow the user to control the Router Advertisement (RA) on IPv6 so it always sends out IPv6 DNS addresses via RDNSS.

I've now got the ER-605 working well, including the BT IPTV streaming. FYI, it required a second interface to be defined on the WAN port alongside the PPoE interface in order to receive the UDP MultiCast packets which are not encapsulated in PPoE. I've posted the solution onto the BT Community Forum so we shall see if it remains there!
cheers

In reply to a post by mhoam:

Thanks for the suggestion.
Yes, I disabled the DHCP server on the SH2 and used the DHCP server on the piHole. This works fine for IPv4 but not for IPv6.
The SH2 does not allow the user to control the Router Advertisement (RA) on IPv6 so it always sends out IPv6 DNS addresses via RDNSS.

I've now got the ER-605 working well, including the BT IPTV streaming. FYI, it required a second interface to be defined on the WAN port alongside the PPoE interface in order to receive the UDP MultiCast packets which are not encapsulated in PPoE. I've posted the solution onto the BT Community Forum so we shall see if it remains there!
cheers

It's great that you have a solution working.

I wouldn't expend any more time nor energy concerning yourself what can or cant be located or viewed on a public forum - especially one run by a vendor. Its theirs to do with as they see fit, including the content on it.

Life's too short. 👍

Agreed, I've moved on

It's their service. Their hardware. Their forum.

Their rules.

Wrong and right doesn't really come in to it. If you don't like it you are free to leave subject to whatever the T&C say about terminating your contract.