I have two seperate solar PV systems, one close to horizontal on a garage roof and one on the house roof.
These two together generate together 9.6kWp.
In total there are 32 180w and 16 240w panels.
Early days, installation just finished but looking good for substantial generation.
Carefully research the suppliers in the market place and fully understand the technology.
There are an awful lot of ex double glazing salesmen out there and some very questionable sales techniques.
Try to pick an established local company and avoid those who have just jumped on the Solar PV bandwagon.