Nat type 2 Strict, PS3 black ops 3

[#1]

Hi, can someone helps please, I have been trying to get my nat to nat open, but I'm having no joy, I have a 2704N fibre broadband, with one of the bt open reach boxes, I have tried port forwarding on port 3074 this failed and made no difference, I then tried to put my PS3 into DMZ this also made no difference, I am pulling my hair out, my game keeps disconnecting and I'm getting really annoyed at how limited the settings seem on this modem.
Please help before I launch the modem through the window!

[#2]

I don't know the 2704N.
AFAIK Type 2 nat on the PS3 is as good as you will get on a shared connection and shouldn't be a problem. IIRC PS3 its self doesn't use 3074, BO3 uses 3075.
If it's the only console on your LAN I would have thought BO3 would have said open in a DMZ - but then comments in the hardware section say the 2704N is a pain to port forward so maybe the settings didn't take - did you reboot it?
If I had to use one I would first try setting everything back to how it was reboot then see if advanced -> firewall -> upnp is enabled. If it isn't  enable and reboot - check it's still enabled and then see how things are then.
Edit: Forgot to say when changing things/rebooting the router shut down the PS3 and don't turn on till the router is back up.
Edit2: If BO3 on the PS3 is anything like it was on the xbox360 then it's well buggy and disconnects anyway 😞 I had open nat on my 360s but it doesn't help a buggy game - you shouldn't be getting disconnects even if nat is moderate.

[#3]

Hi
My ps4 is currently type 2 but blackopps 3 and advanced warefare both say nat open.  Trouble with playstation there type 1 2 n 3 are not always correct I've allways checked with the games as they are what's connecting to the servers.