(1) Where, at the commencement of this Part, there are more than 4 trustees holding land on trust for sale, no new trustees shall (except where as a result of the appointment the number is reduced to 4 or less) be capable of being appointed until the number is reduced to less than 4, and thereafter the number shall not be increased beyond 4.
(2) In the case of dispositions on trust for sale of land made or coming into operation after the commencement of this Part—
(a) the number of trustees thereof shall not in any case exceed 4, and where more than 4 persons are named as such trustees, the 4 first named (who are able and willing to act) shall alone be the trustees, and the other persons named shall not be trustees unless appointed on the occurrence of a vacancy;
(b) the number of the trustees shall not be increased beyond 4.
(3) This article only applies to dispositions of land, and the restrictions imposed on the number of trustees do not apply—
(a) in the case of land vested in trustees for charitable, ecclesiastical, or public purposes; or
(b) where the net proceeds of the sale of the land are held for like purposes.