The “add-on” – from the garage roof – I meant was in regard to roof capacity/space, because of my roof shape. This would be at first installation.
A bungalow, 4 doors up from us has a set-up split on two adjacent roofs at right angles to each-other. HERE. Our roof is at “Bed and Bone” – pointy and split sections.
We would have had an installation done years ago, but they wouldn’t install if building work was imminent and we were planning building an extension, where our conservatory was, and making it into a lounge/kitchen/diner. By the time it was built, they had cut the tariff and stopped free installation!!:(