I think the "82-...blueyonder.co.uk" would be the accurate host/domain name. If you have what I call a "Static/Dynamic" IP, then this can and will change. It's a hybrid of the two. You get a dynamic IP address that changes every lease expiration, but is static until then. Unlike, say, AOL, where you get a new IP every time you log in. My old road runner account had this, where I would have the same IP for a week or two, then it would change. So really, it's dynamic, just at a longer cycle than most dial-ups.
You can also 'reverse' this by typing in "ping -a 82-...blueyonder.co.uk" and it will give you that ip address back.
The line under "Local Area Connection 2" that is blank and says "Connection-Specific DNS Suffix" is where I find my domain name.