The only other malware util I use is spybot and I have tried the same scenario with spybot disabled.
On windows 8.1 I have not used any other version of avast! but the latest. However on a w7 pc I have older version as mentioned earlier and on that Netflix and BBC iplayer work fine unlike on the w8.1 PC
My guess is that because the streams do not originate from a
www.netflix.com or suchlike url but from IP addresses.
As those ip addresses are not embedded into trusted sources by avast database they get blocked. I can see in the realtime data windows a multitude of ip addresses are scanned and presumably blocked...netflix appears to use more than one stream maybe I need to learn all of those and exclude them!
You can see those IP addresses in the pictures I posted earlier.
I will exclude those IP addresses see if it helps.