8.— (1) (a) The Authority may specify different categories of public bus passenger services in respect of which licences may be granted and shall set out details of such categories in guidelines prepared under section 23.

(b) In specifying categories under paragraph (a), the Authority may, among other things, have regard to different types of services, the frequency of services, the scheduling of services and the time of year within which particular categories of services shall operate.

(2) The Authority shall determine the period of validity for licences and, where it specifies different categories of public bus passenger services under subsection (1), it may determine different periods of validity in respect of each category, subject in all instances to a maximum of 5 years.