Port Forwarding - Technicolor TG582n FTTC

[#1]

Hi All,
Apologies firstly, I'm sure that port forwarding is something that gets mentioned a lot, but I am at a complete loss here.
I've been with Plusnet for 2 weeks now, and for the first time a few days ago I decided to forward a port (to run a Minecraft server)
After spending several hours of pulling my hair out, googling for people with similar issues and just sitting in the corner to cry. I finally decided to contact Plusnet support who were nice enough to inform me that they do not in fact "support advanced features such as Port Forwarding"
So here's where I am now.
I have reset the router.
I have created a new game entry called Minecraft, as a test, with the port range of 25565.
I have assigned it to my PC, which is in the devices list (I have also told the router to give the device the same IP always)
As far as I was concerned, as with all previous routers I have used, and as guides online have told me, that should be the whole process.
But alas, if I try and check the status of the port using a tool such as http://www.yougetsignal.com/tools/open-ports/
The port still always shows as closed.
I have also tried turning off the firewall on both the PC and router to no avail.
Forgive my ignorance but could the modem that the router is plugged into (from BT) be blocking any traffic at all?
Thanks in advance,
Will

[#2]

sounds about right, i've got a minecraft server running with that setup fine.
assume you've tried connecting within your lan to rule out anything with the pc your minecraft server is on?

[#3]

Can connect within my network no problem, I've tried several other ports as well, including GMod and Risk of Rain and it never seems to actually forward the port.
Any tool for checking ports online always shows them as being closed.
adie:quote

[#4]

so you've got something like:

[#5]

That open port checking site will only work correctly if you have a server running on the target device which responds on that port.
It may work correctly if you have the game running at the time but a better option is to test with PFPortChecker -- it must be run on the PC you've port-forwarded to.
http://portforward.com/help/portcheck.htm
From what you've said, it sounds like you've done the PF correctly, just not tested correctly, but are you sure it's only the one port you need to forward.
I suggest you enable game mode and UPnP in the router, if you're lucky those setting just might do automatic PF for you.
No need to disable the firewall in the router, but I would disable it in the PC until you've got things working.
Good luck, let us know how you get on.