IP Camera and Port Forwarding Issues

[#1]

I have 2 accounts with Plusnet based at different properties.
I have an IP Camera connected to the Router at one of the properties.
I can normally access it via a DynamicDNS server which checks to see if the IP address of the router has changed.
If I access the camera over the internet at the host location where the camera is located using the DNS at xxx.supracam.net or xxx.xxx.xxx.xxx:81 I can access the camera web interface.  Similarly on the local network at 192.168.xxx.xxx
If I try it at the other location (remotely) with the same method it times out.
I can't really see the difference as both requests are going out over the internet.
Using a Technicolor TG582n which worked until a few days ago and now it's failing.
Everything else works fine and port forwarding is set up.  I know it's set up correctly for that as it connects to the camera through a mobile app and from the host location
  If anyone can help I would be much appreciative!

[#2]

I'm suprised nobody responded with this earlier..
The  Plusnet Firewall being on would be the most likeley reason you can't access the camera remotely but can using the WAN address locally.  Unless it's set to off or low Plusnet will block the traffic.
p.s.  I hope you've changed the password from its default to prevent anyone else from connecting.  A Creepy Website Is Streaming From 73,000 Private Security Cameras