My solar installation team have arrived and now they are getting stuff ready.
(I should have posted this just after 09:00 yesterday, but events sort of conspired against me.)
Anyway, all was up and running by 16:00; and the last couple of hours of daylight produced 0.45 kWh of electricity.
I have also learned that the human eye is utterly lousy for measuring light intensity. But I guess that's why cameras have exposure meters .....