@mhoam 

I have now updated the ER605 to the latest firmware (2.0.1 Build 20220223 Rel.68551) but with no success :-(

All the threads related to the use of third-party routers to access BT TV in the BT Forums have been locked so only BT employees can access them. 

Anybody successfully using an ER605 to access BT TV?

Thanks

  @mhoam 

An update for anyone trying to get an ER605 to view BTTV IPTV channels, my problem was NOT the IGMP Proxy.

BT use a PPoE connection over FTTP and that works fine on the ER605. However, the IPTV streams are broadcast via PIM so are not picked up by the PPoE connection.

I solved it by adding a secondary connection to the WAN definition, I gave it an RFC1918 (non-routable) address. The ER605 was smart enough to automatically add a Route from the IP address of the secondary connection across onto the LAN side.

This second connection picked up the MultiCast UDP packets so the BT streamed channels (BT Sport etc) work fine.

Of course IGMP is also required to ensure the MultiCast packets don't flood the internal LAN

Problem solved!