It seems BT now allow VOIP landline numbers from other providers to be ported in and replace the original BT issued VOIP number on Digital Voice. BT Business have just accepted my request to port my yay.com voip number to replace the Cloud Voice Express number. Haven't been charged anything for the port and been told it will take 2 weeks for the number transfer to go through
It means I no longer have to pay yay £3-£4 each month to keep my very old landline number active.
Time to unpack the Yealink BT VOIP handset again
BT Business FTTP 330/50 -- Netgear RAX200