I have fair knowledge of electronics so totally willing to get the soldering iron out. I have tested most crucial components on ps board with meter and along with visual inspection for obvious nasties like bad caps, agree that board is fine. Was wondering if there was any extra psu logic I guess.
So I know both the screen(MB91 LG UHD/55262 DLED) and panel(ves550qndl-2d-n12) model.
The T-Con board is LG with a TLi2380EP ic.
The board(mb130) serial(? I guess) that is printed along the top beside the PSU connector is [1913 23515696281161620539 1011913957301]
Just in case this helps, I can take pictures etc if necessary. Either to fix, destroy or replace the board

Thanks again for all your assistance