To supervise a learner in a minibus (class D1) or small lorry (class C1) you must follow certain rules depending on when you got your licence.
If you want to supervise a D1 or C1 learner driver, you must have a full licence for the same category of vehicle being driven by the learner. You must have had the licence for 3 years.
If you passed your car driving test before 1 January 1997, you automatically have the right to drive C1 and D1 vehicles, but you’re not allowed to supervise learners in these categories. To supervise, you must:
Pass the theory and practical driving tests for the category of vehicle being driven by the learner.
Wait for 3 years after passing your tests before supervising anyone.