Until I moved here I hadn't heard of Hive Active Heating, but that's what I've got... except that I haven't. 

The installation is someone else's, the previous owner's or the tenant's, who knows, but it's not mine and so I can't set the heating to come on and go off at particular times. I can only turn it up or down in the present and there's no timer on the actual boiler.

My plumber is going to look into it, but to be honest I don't think I want it anyway. I tried to chat with Hive online, they dropped the chat! I tried to phone them and the automated voice said they couldn't take my call! They must have all gone down with Coronavirus.

My plumber's just got back to me, he's going to see if he can fit a timer to the boiler and get me a conventional thermostat. Enough technology!

Edit: the greenhouse has gone, see 
extra.
Edit: of course my plumber went into lockdown and on 3/5/20 Hive stopped doing anything, so the heating is now either on or off. Good job summer's coming.