Oscarmax I’ve had our 4kw system for about 11 years. It generates about 3000 – 3200 kWh per year. The inverter packed in two week before my five year warranty expired so got it replaced for free and the new one is six years plus old and still ? working.
I got in at the very start of the solar panel introduction so I get paid by the government for every kWh produced. I currently receive about £1600 yearly.
I suggest you get a system as large as your roof can provide as you are going to use much more electricity when you go full BEV.