Although of no concern to me at the moment, not having FTTP or DV a question occurred to me having read a number of questions and answers.
Could you de-register a cordless phone from its base station and re-register on Smart Hub 2, to use DV, probably losing some of the functions?
BT have a DeCT adapter that you can order for no charge if you have been moved to DV.
Or you could just plug the dect base station into the green pstn socket on the rear of the smart hub.