So, now is the time we need to decide whether to go for in roof solar on one side of the roof (old Google image for info). Note a lot of these trees have gone and there is no shading.   My other half doesn't think it is cost effective and I'm trying to drive the cost down. We approached two companies, both MCS accredited who came back with some prices which seemed expensive.   We aim to avoid getting prior DNO permission and as I understand it the Peak Wattage of the PV array