Hi; I sort of got it working but only after many hours of toil. Disable auto-detect IP address and put in your local IP adress and your plusnet IP address. This may change if you don't log on regularly so you might need static IP. You may well have to log in to your router to get the Plusnet IP adress you are using. And finally, look up the DNS addresses and put them in too. I used 220.127.116.11 and 18.104.22.168
Hope that works out for you.
I've yet to find out why it won't autodetect the NAT IP. It's either that or it ignores the Never send internal IP box.