Aidan posted this article about the problems many have with plug fouling and never returning to fire correctly often at low life this goes into   thoughts of the ceramic becoming contaminated  which has some credible  overtones https://www.gsparkplug.com/shop/fouling-shortingout-problem-modern-plugs-champion-vs-ngk/ then Andy one of my locals suggested we read this https://patentimages.storage.googleapis.com/23/9c/46/66f4651fa67e4d/EP1434324B1.pdf and after a few pages i