The ground source heat pump is going to extract low grade heat from the ground, and concentrate this into high grade heat in the form of hot water for taps, then under floor heating then the hot tub.
There will be 3 bore holes down which liquid is pumped to be warmed by the heat of the ground, up to a bit short of 100m down !
Lowering & driving the drilling rig down the rear stairs:
The drilling head:
Drilling, with all the dust, which was a lot more than I expected.
Dust on the solar panels that are going to need a clean (or for it to rain so they self clean, apparently).