//Note that if you have completed a speed awareness course within the previous three years, you will not be eligible to take another one,//
With the offence dates being used to calculate the three years. And there's one exception - Dorset. That county does not participate in NDORS - the National Driver Offender Retraining Scheme. This means that if you commit an offence in Dorset and do a Dorset course you can still commit another offence elsewhere in E&W within three years and still be eligible for a course. Similarly, if you do a course for an offence committed elsewhere, you can commit an offence in Dorset within three years and be eligible for a course.