How about, every has to retest every 10 years, within 3 months of their initial pbutt date (solves the back log situation and drivers could be notified just before their date). Failing this retest (maybe a sliding fail scale) may not be an automatic ban until you pbutt.
1)Minor fails on a couple of small but significant points, but car Control OK. you may need to take a varying ammount of refreshers lessons, some theory, some in the car to show you have solved the problem. Car testing done in your car like the IAM stuff. No ban from driving while completing.
2)Nothing dangerous but maybe less than perfect observations, or apparent lack of some car control. Clean license until the test. Lessons and a retest. No ban until you have completed the lessons and failed the second retest at the end.
3)Obvious danger, lack of car control, no knowledge of road rules or safety advice. Lessons, Medical-sight test, and retest. Temporary suspension of license until all completed.
As all drivers are tested and most will need some kind of instruction, this "Fail" shouldn't be something that the insurance should need to know about and benefit from. -- Carl Robson
MPH to KPH30 down to 20 for non-arterial single carriage way roads in town makes sense (ie residential areas) however...