BT home hub6

[#1]

Last year I read many reports and reviews about the plusnet router as I was having stability problems. Many suggested a BT home hub and I have been very pleased with it. Recently I noticed that I could not access my home cctv dvr from the Internet and this had probably been the case since installation.
Technically I have successfully set up rules on previous routers and I believe I have done it correctly on thie home hub router. But no apps will view my dvr including the suggested app.
I know my DVR ip address and Port 80 is open to it.
Using Internet Explorer I can access my DVR and login. Ports 5000 and 8000 are shown as mobile and http ports and both are open to TCP/UDP.
All ports have tested as open using an online porting tool.
It just appears that any apps that I use (many are similar to set up) will not work.
The recommended app used to work on the plusnet router but I don't want to go back to that.
All my tests have been done remotely or through the mobile network. Not when I am connected to the same WiFi as the dvr.
Am I missing something obvious?

[#2]

Would you want random people accessing your cctv/dvr from the internet?

"All ports have tested as open using an online porting tool." - I hope not!

Are using http over port 80?

Have you considered https over port 443?

Hopefully, plusnet's offering is blocking many ports - including port 80.

You can change this.