Hello folks,
I hope the picture shows ok. If it does not show, then basically there is a blue disc approx 25mm in diameter that may have a resistor or something in it. It is approx 4mm ' thick'.
The blue disc is linking between neutral and earth on the fitting. Never noticed these before and the casing of the fitting is live when energised, which is not good!
Fluorescent's puzzle me at the best of times!
Thanks.