Admiarlable – you don't have to tell your insuance. It isn't a prosecution and hence you haven't been convicted. That's the whole point of the scheme, to encourage people to be educated about speeding and the dangers, they pay a fee and hence don't get points or a fine. IE don't get prosecuted and hence you don't have to tell your insurance.
But it is an "incident".
The law on disclosure is that you must declare any fact that a prudent underwriter would take into account when assessing the risk. Failure to disclose such a fact allow the Insurer to void the Insurance and refuse any claims. There is no definition as to what constitutes a material fact – that is for the courts to decide.
The failure to disclose does not need to be relevant to any claim. For example failure to disclose a motoring conviction, if deemed material, would allow the Insurer to avoid paying a theft claim
In practice in view of the draconian effects of non disclosure it is best to err on the side of caution and let the Insurer decide if it is material.
The logic behind this law is that an Insurance contract is very much a one sided affair as far as assessing the risk is concerned. You have all the facts and the Insurer has none. There have been a number of proposals to change this law but Insurers are, understandably very reluctant to go down this path as they see it as their major defence against fraud.
And then there's Utmost good faith. So insurers take what is given them at face value but if something isn't mentioned then it can give them cause to invalidate the insurance. That would mean you don't have to mention the Speed awareness course, like you wouldn't have to mention an IN10 but don't expect to be covered or paying the same price if they find out or you have an accident.
I love this one :) One of the best cars ever. Shame it’s now the ultimate Chav Mobile NOT a Celica as Surf-Mat reckons. 
