@NitrousB
Demon Broadband still uses BT's service, and they can still make life hell for you as I found out to my cost (even though my broadband was never with Openworld as such)
They cut off my service - entirely their mistake - but it took me a week to discover what happened, persuade them they were wrong, and then get my service reconnected. Even though it was BT's fault, I had to go back to my provider and ask them to get me reconnected despite the fact that it wasn't their fault at all, and then they had to chase BT up so that the idiots would get me reconnected. Of course, it was days before BT told me I had to do this, as they kept saying they would be fixing the problem and then ignoring me.