as for will your bb work at a different address short answer no, but if that other address has an active adsl service on it then plugging a router in and configuring it to the isp's settings ect, enable you to have working bb, but it would not be yours it would be the bill payers bb service
In my experience that statement is wrong - Both are apparently BT Internet customers, so unless BT have a radically different set up to other ISPs it should work.
My sister and I are both Enta customers, when my ADSL failed completely (no sync) I called support - who later reported that BT were unable to find a fault (not unusual) and that I should test my router as there will be a charge blah blah blah..etc. I took my router over to sis, plugged it in. and successfully logged on with BOTH user names - in fact when I called back Enta to report that not only did my line not work with 2 known working routers , I was able to log into my account with both routers from another location with an Enta line the tech commented that he could see from the logs that I had briefly logged in.
This was the second time a fault couldn't be found by BT and a visit booked for a fault that miraculously cleared after BT "ran some tests at the exchange". .... although I still cant get the BT speedtester to work on my line.
Any ISP that thinks that selling my click traffic is acceptable is MisinPHORMed