moving back

Am currently in the process of moving back to B.T. from Tiscali LLU.

Talked to B.T. and they said they can transfer telephone service no problem
but what im unclear about is the Broadband.

Obviousley I need to do this seperate from the phone but do I need a MAC
code? Until the line is back with B.T. the broadband line checkers will not
reconise the number as a B.T. line so there will be some downtime?

If Tiscali employ stalling tactics I understand if I ask for a B.T. new
number this relinguishes Tiscali's hold on the line as a renumber ceases any
broadband, is this true?

Thanks.