Free Traffic Legal Advice

First speeding ticket ever in 19 years of driving. I'm in denial (of course  ) because I am generally a speed-conscious driver. And I have lived in London since 2006 where it's like an obstacle course not to get done for something on a daily basis.

Anyway, this seems incredibly draconian - particularly as the guidelines suggest 10% + 2mph as the start point for prosecution to avoid constantly prosecuting for minor infringements. This is so on the edge, do I have any hope of challenging?

With it being the first offence I'll probably get the option of SAC - and no fine or points.. but I'm still miffed to accept it!

As you said, enforcement begins at 24mph, so you've seen that enforcement. It would be somewhat pointless if the police operated to those guidelines and then accepted "challenges" from drivers who are recorded at that speed.

You should be offered a course for that speed.