@Rain-or-Dom With the difficulties that the 7+ and also potentially the other EE Hubs as well that has yet to be fully confirmed, the uPnP getting in first does appear to very much so upset the table, EE CS will be off zero help as PF is just not done by many and even from your example posted looks good, so until the FW bods get there hands on it all and correct whatever issue is found the work around does need to be followed. It is a bit off a mess having to Factory reset but that is the only way to clear out the PF rules 100% so you can start and get the required in, uPnP has it's place but if you are like me you do want to have it switched off and do your own.
All the DMZ placement of the IP is a get out of jail for TESTING only to see if everything is working and the EE Hub is the problem, if used bypassing the Firewall off the EE Hub then you have to make the decision that the device's own Firewall is going to stand up and be counted....
Well done @Rain-or-Dom and was nothing that i did, all down to you sorting it out and getting working on your network.
