We have a boiler in the utility room, cold water tank and header tank in loft, and hot water tank in the bathroom.
We have Hive and we have a British Gas Homecare 2.
We've had British Gas out at least 3 times for this and they've not been able to find a problem! 
Basically we have the hot water and central heating come on twice a day using the Hive app and occasionally we use the boost for both on the Hive app.
However, 9/10 the receiver says that the hot water and heating are not on but the boiler is still going. The boiler is ignoring the signals to turn off. The only way we are able to stop this happening is to physically switch off the boiler. And switch it on again. Which is obviously inconvenient. Especially in the morning.
When this happens we can hear the boiler running and the radiators on the first floor are heating. But the hot water doesn't seem to be heating.
As I've said we've had British Gas engineers come out a few times and said everything is ok. We've uninstalled and re installed the Hive app etc.