I recently purchased a Siemens handset (Gigaset N300A) which is infinitely superior to the Yealink W70P provided by BT.
Installed the base station and it was recognised on the network, linked a handset to the base station but it would not connect. Calls to BT support eventually identified that BT do not support any other product other than the Yealink or Cisco phones supplied, and no support or assistance could be provided for non BT kit.
This is not advertised at all and should be made more widely known. Gigaset phones returned and thankfully a refund received.
My question is there any other supported BT kit for BT Voice express with a better spec than the Yealink W70P. I particularly need better speaker and Bluetooth connectivity as I am somewhat deaf.