Quoted from cyberkryten:
I've only just realised that the triangular signed cards on my LE at the bottom of my playfield should be illuminated.
Looking at the manual, these both seem to be on Lamp #277 along with the rest of the lower play field GI so I don't think its an issue with Node Board 8 (but I disconnected and reconnected the connector CN15 anyway which made no difference).
Spent a while going through this earlier, connected a spare LED on the output of the lower playfield connector and it worked fine, which meant it wasn't the main loom which was a relief.
So I took off the top cover and found that where they'd cable tied the LED board to the post, when cutting the excess cable tie it had sliced right through the LED feed cable. Put a joint block to connect the two halves and both the LEDs are now working