I've just tried to install the 2762 at home and the IPTV freezes after a few minutes and then throws the IPC6023 error.
If I change to another channel/stream it works again for that channel for a while and then stops again.

I have enabled IGMP Proxy in the applications menu,
There is an interval value, which I have left at the default 25 seconds.
I have left the IGMP version on Auto.
I have tried with and without the Snooping turned on.
I am using the BT Youview UHD box.

Any help would be great, as my current setup wit an old Cisco 867 requires the YouView to have its own LAN and VPN is a pig to set up in IOS.

I've got a 2960 and to fix the issues I had to the following so I would look at your firewall and then the system logs.

I may have fixed it although some of the steps I have done before with zero result.

Step one Create a policy route so that all traffic goes via the appropriate Lan in my case wan2. This has been present from day one.

Step two Under Nat port redirection make sure ports 1024 to 8081 go to the ip address of your youview box. This rule has been in and out over the months

Step three Under applications make sure igmp proxy is enabled. Set to the wan that your BT provider is on in my case wan2 Without this you can't tune the internet channels .

Step four Untick PPP header (Only a recent addition) Prior to this firmware 1.4.0 unticking or ticking made no difference

This will result in stuttering picture

Syslog will show UDP flood

Step five Under the firewall disable UDP flood

Now you'll be able to watch BT channels for about two to five minutes until you get ipc 6023 error

Step 6 Under Firewall disable the following

Block IP channels
Block Land
Block Smurf

However something changed over last summer and I would get drop outs.

This was due to many mulicast packets which the 2960 blocked and so Draytek game a beta version where the threshold for FPP was disabled which allowed me to watch youview again. It's not perfect I may get the odd break up but can generally watch 90 minute sof football with perhaps only one brief one so I'm putting up with it.

I increased the IGMP General Query Interval to some hours rather than seconds and it sorted it. Should have posted earlier.

Excellent, that's useful to know, I was expecting your problem to be caused by UDP flood defense

3.9.2 seems to break this. My BT Sport kept stalling and throwing up an error. Went back to 3.9.1 and it works again.

My BT freeview stopped working without firmware change so something changed at BT end. After a few diagnostics back and forth a new feature was added Fast forward under IGMP proxy which fixed the issue.