its an old white bt home hub if that makes any odds?
Try this: http://www.filesaveas.com/bthomehub_portforwarding.html
Basically you have to set a rule on your router to tell it where to forward an incoming IP packet to. This is because you can have multiple machines on your home/shop (private) side of the router, but you only have a single ip address externally.
Port mapping is used to solve this problem, an incoming IP packet has a destination IP address (your router) and a Port number. The router has a table of which port maps to which machine on your private LAN, and will swap the destination IP address of itself to that of the target PC on the private side, so your incoming request finds the IP camera and not your laptop, or PS3 etc.
So if your IP camera has an IP 172.24.0.5 and you connect via http, which is port 80 and your external (public) ip address is 1.1.1.1 (for example), you need to pick a random port, say 8081 and map:
1.1.1.1:8081 to 172.24.0.5:80
To externally access the webcam you point a web browser at:
http://1.1.1.1:8081
You need the ‘:8081’ to add the port number otherwise it will default to 80.
It all seems a bit complex, but if you had multiple web cameras you could map them all thus:
1.1.1.1:8081 to 172.24.0.5:80
1.1.1.1:8082 to 172.24.0.6:80
1.1.1.1:8083 to 172.24.0.7:80
and now you can pick one of three webcams, all using the same single external ip address.