Update to this. After a rather shaky start it's all up and going. Speech sounds way better that the old analog setup though I still think that fiber would have been better. The only issue was that the end user assumed that the DECT cordless in her room would work off the new one she had bought to plug into the router. Spark are sending out a twin set of Uniden DECT phones that should fix that issue though a triple set would have been better.
The only this that seemed odd to me was that she couldn't access the internet from her desktop PC via Ethernet until she had put in the WiFi password on the base of the router.. Once she did that the Tablet and cell phone WiFi then also burst into life..