Where is your current thermostat ?
I don't have one. Heating is turned on/off using a mechanical timer switch attached to the boiler currently.
Where is your current thermostat ?
Run a wire to a new thermostat position
I'm very happy with my Hive, and was in a similar situation where there wasn't any neat way to wire up a Nest thermostat. I've had it nearly two years now, I think I may have replaced the AA batteries once but I can't actually remember if it was needed or I just unclipped the thermostat when I decorated the room.The stat would need to go in the stairway. It's the only suitable room. And it's going to be very difficult to get a permanent 12v feed there without taking carpets and floorboards up and making holes in the walls. Same for putting a socket in. And even so, it's not going to look good with a wire dangling down the wall to the socket.
Hive seems much more convenient.