If you commit another speeding offence within 3 years you are not allowed to go on another speed awareness course.
Only the police have access to who has been on awareness courses and this information is held on the police computer. As I understand it, a roadside check by the Police will not show up a speed awareness course, presumably this will only show up on a secure terminal...at least that's what I've heard.
Pete
And even then it's not just one database, as it's different for each county i.e. You get caught in one county, you do the course (You then can't do it again for 5 years I think) But if you get caught in another county, you can go on the course again. So I've been told as it happened to a friend.