This thread explains much of what I've been seeing of late, with some webpages only seeming to half load and others never apparently finishing to load.
If the trend continues, and more and more normal web content ends up on CDN networks, then with or without fine grain control, I feel Plusnet are going to have to increase the priority of this kind of traffic. Now that I have a better idea what I am seeing I will watch it more closely.
As for net neutrality, so long as an ISP targets traffic/protocol type I'm thinking ISP's will be OK and customers will choose with their wallets what they find acceptable and not acceptable. However, if they are discriminating against other ISP's, specific hosts, IP's, companies etc that I expect ISP will be finding themselves in court when large companies take umbridge, and in the court of public opinion and the press when it comes to smaller companies who cannot afford the courts.