@wills106: I don’t - remembering that I have a cold blooded wife and daughter, and I’ve exposed a 30min boost (aux_heat, which boosts hive for 30mins @0.5c above the current temperature of the hive thermostat) via the Eve iOS app, during winter I expect a bit of overshoot 
. However in comparison to the previous 1-5 type thermostatic radiator valves, it’s night and day - what the bloody hell does 1,2,3,4 or 5 mean?
However, my greatest benefit (central heating wise) has come from installing the external temperature sensor (called different things by different manufacturers, but essentially it’s a thermistor of a given value which alters the resistance of a circuit on the boiler PCB allowing it to gauge the outside ambient temperature in terms of a resistance value). This means when it’s mild (like today), the hot water circulating through the radiators is of a lower temperature than a day when it’s sub zero outside.
The knock on effect for me is that when the hive thermostat reaches the setpoint and starts the shutdown sequence for the boiler (which includes a 10 minute overrun to prevent boiler damage), on a warmer day like today where it’s been up to 10c outside, the water in the rads has only been around the 50c-60c mark, so much less thermal mass and much less overrun - not allowing for my boost fanatics of course!
Judging by your one or two degree overshoots, that’s not bad IMHO, but I’m comparing to before I had the Spirit TRVs where my overshoot could be as much as 5 or 6 degrees.
What is the water temperature in your rads when you get the overshoot? Do you have an external temperature sensor on your boiler?
I also have two separate inbuilt stats on our boiler, one for SL1 (C/H) and one for SL2 (DHW), so I can individually set the max temp if I disconnect the external sensor - do you have something similar you could use to adjust the temp of the water?
At the end of the day, when the setpoint is reached and the boiler switches off, there is still the residual heat of several hundred litres of scalding hot water (potentially) sitting dissipating heat for half an hour or more after everything is “off”, which I suspect is what is mostly to blame for the overshoot.
I agree about the Hive, I often find the boiler has fired and is heating, but the manufacturer’s own Hive app doesn’t reflect it. I think the Hive integration (rendii) default update interval is 4 mins IIRC. The Sonoffs I’ve deployed with temp sensors are all set with a “teleperiod” of 30s, so it is very sensitive, with no effect on my MQTT instance whatsoever. The out of the box setting is 300s (5 mins) which is probably more like what the Hive stats update frequency is!
Of course now you’ve mentioned it, I’m going to go obsess over my new infuxdb/grafana reporting capability…
(only set it up two days ago, so not enough data yet).
