Just out of interest I've tried this with my cisco router which has multicast pass through option and the draytek 130 and no joy either.

Dug out my old 2920 enabled ppoe enabled igmp proxy and igmp snooping and the youview box worked. So it's an issue with the 2960.
Draytek support have been in contact so I just need them to get the 2960 working if they can.

well for a laugh I decided reset the 2960 to default and see what happens. Well even worse won't even tune in the extra channels even with the original restored

Well I told draytek that the vigor 130 worked with a draytek 2925 when I mean't 2920 so they've told me to flash the 130 with the reset file ?????

Since I've proven that the 130 works and it's the 2960 which isn't doing the right thing I can't understand that unless they haven't seen my later emails or just pressed the delete key. I've now offered to send my backup config file.

At the moment I'm building my own router out spares I've got intending to put pfsense onto it. If that works and delivers the through put the 2960 can go back on the shelf.

In the meantime I've got the subscription channels back by adjusting a previously working rule.

Still ongoing tried a beta version of the software no difference. The beta would cause the web interface to crash out so Draytek couldn't connect. Sods law then dictates after I reboot the router the ip address changed so I decided to revert back to the original firmware as it pointless having a beta firmware if it crashes the web interface.
Draytek have now pushed the issue up the ladder to Taiwan.
It's partly working as I can see the log files the packets going to one machine after another. If I had snooping I could force the multicast to one port which I suspect would fix the issue.

Draytek still haven't found a fix but still trying to.