Solar PV so far so good. Generate about 3,000 Kw pa. Don't like the fact my supply soon stopped trading. Don't know where to go if anything fails.
Central heating: Tried sensitive valves, magic box, improved control panel and something that removes oxygen. Not sure any did any good energy wise. Control panel I liked. Central heating a lot quieter - I like that.
Had an Energie water heating tank fitted. It works very well but has drawbacks. No one knows how to service. Service is minimal but it has some. Panel fitted on North roof, has failed in winter - covered in ice. The distance of the tank from hot water taps is a big issue. Takes ages for hot water to arrive.
Energie tanks: Make sure distance from tank to kitchen is a short as possible. Don't fit thermodynamic panel on North facing roof.
Be cautious about magic box or any central heating improvements, you may well not make your money back.