You were right. The valve was ok in that it was working fine for the Vaillant controllers whick worked using L/N/E only. I reinstated the grey/orange switch wires for Hive but there was obviously a fault there. Installed a new actuator on the valve and all is good. Many thanks for your direction.
Sorry to bring this topic up again but I thought I had it sorted but the heating is only working upstairs (zone 1)
I originally had a VRC 470f stat and VR 61 mixer module but the 470f has finally given up after 4 years of suffering - and my god have we suffered!
I removed the VRC 470f panel...