Notwithstanding the provisions of regulations 232, 233, 252, and 256, in the case of a school bus registered prior to 1 April 1991—
| (a) | the number of persons permitted on any seat shall be determined at the rate of 330 millimetres per person, measured at the widest part of such seat with the doors closed: Provided that the provisions of regulation 231 shall not apply; |
| (aa) | the top of which shall be at least 300 millimetres from seat level; and |
| (bb) | the bottom of which shall be hot more than 75 millimetres from seat level; |
| (ii) | be of a height, from the floor or footrest of such seat to the seat level, of at least 300 millimetres and not more than 460 millimetres; |
| (iii) | have a depth, from the front of the seat to the front of the backrest thereof, of at least 300 millimetres; |
| (iv) | have a width in accordance with the provisions of paragraph (a); |
| (v) | where such seat faces in the same direction as another seat, have a horizontal distance at seat level, between the front of the backrest of such seat and the back of the backrest of the seat in front of the first mentioned seat, of at least 530 millimetres; |
| (vi) | where such seat faces a partition or similar obstruction, have a horizontal distance at seat level, between the front of the backrest of such seat and such partition or obstruction, of at least 530 millimetres; and |
| (vii) | where such seat faces another seat, have a horizontal distance at seat level, between the fronts of the backrests of such seats, of at least one comma zero six metres; and |
| (c) | for the purpose of determining the number of persons who may be carried on such bus, the mass of a person together with his or her personal effects shall be taken as 45 kilograms. |
