In reply to gav:
I have done but whether I get anything from it - no smart meter and no contact with Octopus.
I got the panels installed but had very little time to research before or since (very busy last few years with 2 house moves, health scare, busy job and a baby - basically I get to the end of the working day and I just want to go for a run or spend time with the boy, not spend my time learning about electricity). From brief glances over forums etc. there's lots of stuff for people with time to learn (e.g. my retired father) or passing knowledge of electrics, which is just hyper-confusing for me.
The Sunsync app is quite good but some of the interfaces are confusing and I haven't looked at it in months. I know it's producing electricity but I don't know what all the different bars mean. Again, they have lots of youtube videos but they are all focused at installers or people with time and inclination to learn this stuff.
I've been tracking my grid energy usage as per my meter readings and comparing against the few months between moving into the house and getting the panels installed. There's been negligible reduction in energy usage per day.