Rules for Teamspeak 3 on non-standard port?

[#1]

My WoW guild uses Teamspeak 3 for voice communication while we play.  Unfortunately, the virtual server we use is not the published "standard" port for TS3 (our server is on 9122) and in the evenings I am getting latency of 1000 to 4000ms, making real-time comms quite difficult!
Wireshark confirms that this is a simple traffic management issue - it's getting silver instead of platinum.  I raised this in a ticket a while ago and got fobbed off by the CSR saying that because it was a non-standard point you couldn't detect it properly.  Now obviously this is unacceptable but I'm not going to go raising another ticket to get the same response, so any chance a PlusNet staffer who knows what they're talking about can interject some common sense into the debate?

[#2]

puffin,
From looking at the details on the ticket we can certainly agree that this is caused by the traffic being managed as silver, however whether or not we should be managing this as platinum is another matter.
The answer previous answer that you were given did come directly from a customer support agent , I have passed this issue back to our networks team on ticket 33443800  explaining the issue and requesting a check if port 9122 should be managed as platinum traffic.

[#3]

That's great, thanks, Adam!
And looking at the Traffic Prioritisation Guide it does look like I've made a mistake: VoIP is Titanium, not Platinum.  (Has Titanium always between Gold and Platinum or is my mind going crazy?).