Henry - the legislation you're thinking of is the New Drivers Act.
This only applies for the FIRST drivin test you pass, be it car or bike.
Subsequent passes are dealt with as per normal totting up rules.
This affects you if you first passed your driving test on or after 1 June, 1997.
If you reach six or more penalty points within two years of passing your driving test (ie during the probationary period), the Driver Vehicle Licensing Agency (DVLA) will automatically revoke your driving licence when notified by a court or fixed penalty office.
To regain your full licence you must then:
obtain a provisional licence
drive as a learner
pass the theory and practical test again
Penalty points counting towards the total of six include any you incurred before passing the test, as long as the offence took place not more than three years before the latest penalty point offence.
Points imposed after the probationary period will also count if the offence was committed during that period. Passing the retest does not remove penalty points from your licence, and if the total reaches 12, you are liable to be disqualified by a court.