The statement "It didn't seem like all packets over 443 were being blocked, just the encrypted ones" cannot be true therefore, as if it's not encrypted it will go via a different port e.g. port 80. What Netflix have convinced you of here does not seem accurate.
If we go back to basics, if you connect just one device (ideally a phone or iPad type device that is less likely to have any kind of malware), and disconnect everything else, does Netflix still not work?
You got any custom DNS, malware protection, firewalls, edited any router settings beyond factory settings?
Here is the most likely answer:
1. Virginmedia is not blocking netflix - imagine the uproar if every customer could not use it.
2. Virginmedia is not blocking port 443 - port 443 is used by many things, netflix, online banking, instagram, facebook, twitter, snapchat, dropbox etc - if we assume they are blocking port 443 we are to believe virginmedia users can basically not use their internet. Again imagine the uproar.
I think time to go back to the drawing board on this one. To rule out the machine, can you set a phone up as a hotspot and confirm it works fine via that? ie outside the virginmedia network.
Edited by ukhardy07 (Sun 18-Mar-18 20:29:55)