(1) It shall be the duty of every director of a building society to satisfy himself that the arrangements made for assessing the adequacy of the security for any advance to be fully secured on land which is to be made by the society are such as may reasonably be expected to ensure that -
(a) an assessment will be made on the occasion of each advance whether or not any previous assessment was made with a view to further advances or re-advances;
(b) each assessment will be made by a person holding office in or employed by the society who is competent to make the assessment and is not disqualified under this section from making it;
(c) each person making the assessment will have furnished to him a written report on the value of the land and any factors likely materially to affect its value made by a person who is competent to value, and is not disqualified under this section from making a report on, the land in question;
but the arrangements need not require each report to be made wi