That didn’t work because I was wrong. You were obviously right CountryFan about belling the wire.
I’ve used a multimeter and found the other end of the grey cable and it’s in a connection box that’s a few feet from the wiring centre (as per the photo).
I’ve connected to the neutral (blue)...
This forum has been incredibly helpful — I successfully replaced a broken Danfoss FP715 heating and hot water programmer with a Hive system.
I’ve now decided to tackle the second heating zone because I really like the Hive app and functionality.
I'm having an issue with wiring the Hive Single...