I’ve had a 4 kw array, cost ~£14k, for 12 years, so get the full FIT. In cash terms it was paid for in 8 years, but as I only started keeping records when they were fitted, I can’t tell how much leccy I haven’t used, but I would guess it probably took the return back to 7 years. In the past 4 years I’ve received £3500 in tax free FIT.
For interest my roof is a few degrees West of due South so arguably ideal, yet a neighbour who had a similar array fitted split between each E/W roof face only 6 years ago, (roof is at right angles to mine) generates ~ 10% more than me. I assume that this due to more efficient equipment.
I cannot understand, given climate change, energy costs etc. why it is not mandatory to fit solar roof tiles to new houses, or could it be that a Conservative Govt. receives financial support from energy companies?