I have to admit having done an online speed awareness course recently (59mph on the M62 in a 50). Got zapped by a fixed camera, but in the preceeding stretch the variable speed limit had changed between 50, 40, then 60 , so in a moment of inattentativeness (is that a word?)......not an excuse I know, but there we go....
I did learn that if you attend a course for a particular speed offence (such as for a 50mph offence), and within the 3 years get nobbled by a camera for another speeding offence but in a different speed category (such as a 60mph), then you are eligible to attend another course. If you did two in a 50mph, then no, but if one was 40 and the other in say a 60, then you are eligible for a second course, even within the 3 years.
That came out on the course, so I presume it is correct, although I won't be risking it just in case it's not.....