Seems they have photographic evidence of a certain 406 'contravening a red traffic light' by a margin of 1 second and have served yours truly with a notice of intended prosecution.

I may be eligible to stump up £92.50 to attend a course instead of persecution.

The alterantive looks like £100 fine + 3 points, so I won't be joining that queue.
Guess I'll get them to send me the evidence just in case there's some haggle room, but I'm not optomistic.