Lightning damage! Couldn't track the fault, only that it appeared to be on the main board: part fried chip I think. I don't keep things any more as I tend towards hoarding and live in a small house with an unexpectedly enlarged family. I found similar main boards from differently labelled TVs but all with subtly different layouts (and codes) and prices just too large (for me) to warrant giving it a go.

Bad caps, I feel like Dr House trying to find Lupus, it's always suggested but never appears ... waiting for that one time to show up.