(1) For the purposes of section 156 of the Act, a vehicle is permitted to be driven only by the holder of—
(a) a driver's certificate issued under section 156 for the class of vehicle being driven; or
(b) a driver's certificate issued under section 156 for a taxi-cab.
(2) Sub-regulation (1) does not apply to a person who is driving a commercial passenger vehicle if there are no passengers being carried in the vehicle for hire or reward and the person is driving the vehicle—
(a) solely for private use; or
(b) to test the vehicle; or
(c) as a trainee driver under instruction.
(3) Sub-regulation (1) does not apply to a person who is driving a private omnibus—
(a) to test the vehicle; or
(b) as a trainee driver under instruction.