Constant disconnects with Technicolor TG582n. HELP!

[#1]

Hi folks. Please bear with me as I'm a newb at this.
So I have the above router connected via ethernet to my ps4. This should provide a pretty consistent service, or so I thought. After getting kicked off of party chat and Destiny for the billionth time I decided to try turning game mode on in router. Same issues. Assigned ps4 a static IP. Same issues. Forwarded ports for ps4 provided by portforward.com. STILL the same.
I tested our connection and pingtest.net gave it a C. Then a D.
Streaming works fine wirelessley. So why won't an ethernet connected ps4 with open ports and a static ip let me get through ONE game of Destiny MP?
Please help if you can...

[#2]

Moved to Gaming to enlist the help of the gaming community here.

[#3]

IMO the router is crap for gaming.
Final things to try:
Get plusnet to do a fault check on your line
2 put ps4 in dmz since it is crap at port forwarding.
If that doesn't work then get a new router as it's likely to be at fault.

[#4]

Thanks for the reply. How exactly do I put the PS4 in the DMZ?

[#5]

Try the search forum method. It's been asked and answered enough times

[#6]

Your line isn't dropping a lot that we can see anyway

Your line itself looks as good as it's going to get on ADSL (there's no 21CN available for you)
Upstream  Downstream
Loop Loss:  6     11
Speed:  448     8128

Quote

I tested our connection and pingtest.net gave it a C. Then a D.

That's odd. What ping results do you get if you open a command prompt and try pinging bbc.co.uk or similar.
It's worth noting that Fibre is available for you too.

[#7]

your upstream looks capped. That won't help. Ask PN to uncap it for you.

[#8]

@Mathias
Unfortunately the only option on a 20CN circuit is Max Premium, that costs and additional £7.83 per month.