My understanding is that all of the wells in the next series...

My understanding is that all of the wells in the next series will be drilled from the one location as a series of step out wells. This makes them less expensive for two reasons. Firstly the rig doesn't have to be dismantled and moved and secondly the piping is much cheaper. Stepping out the drill means that the pipes travel in more or less a straight line from the hot rocks to the location of the power station rather than coming up to the surface, bending and running along the surface. There is probably a safety issue as well. Pipes full of superheated, high pressure water would need to be isolated from workers. Keeping the pipes well underground keeps the workers much safer.

Hydraulic fracturing of the granite produces essentially horizontal cracks that relieve the pressure against the lowest direction of stress. Horizontally, the stress is against a whole continent while vertically the stress is against 4km of sedimentary rocks. The granite is probably less like maltesers and more like peanut brittle that has been hit with a hammer; cracks all over the place but pretty tightly pressed together all the same.

The granite is likely to be 10km thick or more. Below would be intensely metamorphosed rock or even more igneous rock all the way to the mantle. Above, is a seal that has formed as hot brine from the granite has risen and cooled. This cooling precipitates out silica, which seals off the cracks and which continues sealing off cracks as they form. A similar process happens in artesian bores which gradually become choked off with mineral deposits as the artesian water cools.