For the sake of completeness, the relevance of it being a "first offence" is simply that other than the speed alleged being not greater than 10% +9mph above the limit. the other criteria for being offered a course is that he had not completed that course for an offence committed in the 3 years prior to the current offence.
Other than being offered a course, asking for leniency is pointless unless there is some compelling mitigation that you have decided not to trouble us with. It's pretty much a sausage machine/paint by numbers.