Sergio, thank you. 

Octopus claim they do not require an MCS approved installation although it is not so clear cut what they do accept instead.

https://www.renewableenergyinstaller.co.uk/2023/10/clause-5-8-has-octopus-really-removed-the-solar-certification-requirement/

Not sure if others will follow. If they do it will presumbaly sink the MCS ship.

Mike

Courses seem to be a matter of £hundreds, but I wasn't intending to become "accredited". I know what you mean about working at heights, etc. too. Maybe not such a good idea after all.

Thank you all for your contributions.  A bit more elaboration, I was one of the early adopters and have the benefit of the highest FIT rate 68.3p per kWhr generated plus 4.81p for half the units, assumed to be exported to the grid, equivalent to 70.7p per kWhr.  At the time the installation was expensive and there were significant risks on the payback period.  I confess to be surprised at the low cost of modern panels.

I suppose my concern is that having disconnected the panels they will be outside the FIT scheme when I reconnect them.  Like Simon Barker my panels are 190 W, so 3.23 kWp for the system.  My roof does not face due south so I rarely get more than 2.5 kW.  Replacing them with higher power panels would not be quite as straightforward as I would have to upgrade the inverters as well, and lose the FIT, and I already export more than 50%.