This job was sitting on hold for a while, so I've only just followed up on the lighting question.
I spoke with the building control guy at the local council about the "automatically switches off when not required at night" stipulation, and he said they've been told to interpret that as meaning that a PIR motion sensor is needed. So it's either a 40 lumens/watt or better light fitting, or a lamp not exceeding 150W with daylight and PIR motion sensors.
However, the person I spoke with was actually very sensible for an NNDC employee (miracles do happen!), and immediately acknowledged both the unclear wording and all the absurdities we've discussed above. He said that as far as he was concerned, he wasn't at all worried about the PIR sensor, and if the homeowner wants a couple of lanterns with regular filament lamps just controlled by a switch, that will be fine.
