Hi Alex, there is a very good reason I mentioned modifications, the thing in my original photo, that looks like an old fashioned school radiator, is an old selenium bridge rectifier. They have a life expectancy of around fifty years, yours is due to fail. It will smell of garlic when it does start to fail, please don`t breath this in as it can cause cancer.
It s a very easy fix to replace the selenium rectifier with a more modern silicon rectifier and heat sink, all the parts are available on fleabay for about ten quid. No, I am not trying to sell you something and no, I can`t come and do the work for you. I live in Northern New South Wales , Australia. I live in the middle of nowhere and rely on a old 1970`s Lister/Brush generator for back-up power. If you rely on your generator for primary power you should replace the selenium rectifier before it fails.
Where in Berkshire do you live? I was unlucky enough to go to school in Pangbourne, Berkshire.
I completely understand your concerns regarding starting handles. Many full grown men have been injured by these, children do not belong anywhere near them. If you are hand starting your generator please regularly grease the shaft and ratchet pin so you don`t get hurt.
Bob