We would be senario 1, and we leave the heating on 24/7, it kicks in when it needs to. One of the reasons we went for ufh and geothermal was the ease of use, no messing with timers, turning off radiators etc.
We went away for 2 weeks over the summer, and just turned the heatpump down slightly, so the house was kept warm, and the large cylinder of hot water keep hot. We felt by turning the system off completely it would end up costing more to reheat the cylinder, and the house.