This depends on various factors which are presented after your solar survey. The expectation currently is between 6-10 years.

Cloudy, sunny, bright winter and all the weather in between. Solar generation is efficient for UK weather. Though there is no generation during night time, the battery systems offset any demand later in the day when generation stops.

See some more information

Cleaning, testing cabling and equipment, checking efficiency via app and software are all important. Though a system is designed to installed then set up and left to run without any alterations.

https://www.hiesscheme.org.uk/solar-panel-maintenance/

• check suitability and book the work
• install control and battery equipment
• install cabling and DC strings
• put panels up
• commission system

The timescale usually is between 6-12 days for domestic and light commercial systems. Often with little internal disruption to the property.

The short answer is YES. Since a solar panel costs around 250kWh to produce then produces around 100kWh per year, the carbon payback is in the region of 2.5 years. A panel lasting 25 years would therefore generate 10 times more energy that it cost to produce.

https://www.renewableenergyhub.co.uk/main/solar-panels/solar-panels-carbon-analysis