Have recently installed an Evohome controller with 8 separate zones controlled by HG92 valves on the radiators and a Honeywell BDR relay for communication with the boiler. We have an Valliant Ecotec 831 boiler that is about 6 years old. It has been running for about a week and optimisation is not being used

1. Last night (3am) one valve suddenly registered 0 degrees. After 35 minutes it then registered the 15 degrees I was expecting.
Is this a faulty valve or is it a loss of communication between the valve and the controller? No other valve had this behaviour. The valve itself is showing no sign of low battery. We do not have animals so there was no change in the environment or the path to the controller.
Any suggestions?

2. I am monitoring performance with Domocitz on a Raspberry Pi. Overnight it appeared that all the zones demanded/received heat (as indicated by the rise in temperature on the HG 92 ) even though all zones were on the set temperature. Is this just the evohome algorithms predicting that the temperature is about to drop and bring in a small demand early. If so why would the overshoot be up 1.5 degrees before coming back down. In addition the registered temperature never went below the set point unlike the oscillation around the set point when set at higher temperatures

3. People on the forum seem to indicate a small saving of energy with this system. We were looking for increased comfort rather than gas savings but current indications are that we are using slightly more gas than when the house was run via a single thermostat in the hall. I wonder if part of the reason for this is the fact that the oscillation around the set point in the morning starts at a 2 degree swing before settling down. Is this size of oscillation normal? Will this decrease as the system "learns" the environment? Does the system "learn" the environment with out Optimisation.

4. Finally a request for help in locating a Honeywell HG 180. We have found them for sale in the European mainland but no-seems prepared to ship to the UK. Not being able to monitor the demand on the boiler means we are trying to understand the system with only half the information.