67.—(1) Where, during an approved training course, more than one person is receiving on-site instruction and practical on-site riding as part of elements (B) and (C) of the prescribed training course—
(a)in the case of instruction or riding which may under these Regulations be conducted by a certified or an assistant instructor, there shall be no more than four such persons in the charge of any one instructor at any one time,
(b)in the case of instruction or riding which must under regulation 64 be conducted by a certified direct access instructor, there shall be no more than two such persons in the charge of any one instructor at any one time.
(2) Subject to paragraph (3), when riders are undertaking element (E) of the prescribed training course—
(a)there must be no more than two riders in the charge of any one certified or certified direct access instructor at any one time, and
(b)the instructor must be able to communicate with each rider by means of a radio which is not hand-held while in operation.
(3) The requirement specified in paragraph (2)(b) shall not apply in the case of a rider who is unable, by reason of impaired hearing, to receive directions from the instructor by radio where the rider and the instructor are employing a satisfactory means of communication which they have agreed before the start of element (E).