You may be thinking of your driving licence and what it permits . . .
The DVLA appears to say . . .
If you passed your driving test from 1 February 2001
You must complete a compulsory basic training (CBT) course to activate your full moped licence after you pass your car driving test.
If you have a valid CBT certificate when you pass the car driving test, it activates your full moped licence immediately.
You can then ride a moped (up to 50cc) without L plates. You don’t need to take the full moped test.
You can ride mopeds for as long as your car driving licence lasts.
You passed your driving test before 1 February 2001
You can ride a moped (up to 50cc) without L plates. You don’t need to take a CBT course or take the full moped test.
You must take CBT if you want to ride anything larger than a 50cc moped.