1. Before asking BT for a house move tell BT you require a SIM PROVIDE CODE FOR THE O2 GROUP (this is very important or you will end up getting a WRONG VOL code which BE will not accept) SIM Codes start "DFQ..."
2. Ring BE and supply them with (A) The sim provide code. (B) the Telephone number and address of the new property. (C) The date which BT have given you that the new line will be activated.
3. Sit back and relax
If these steps are not done in the correct order especially number 1 then be prepared for a long wait as you will most likely end up losing your connection and have to wait around 14 days before getting a new BE connection.
Good luck hopefully if you follow the steps correctly your BE connection will work the day your new line gets connected.