(1) Subject to the provisions of this Part, the trustees of a trust may appoint a person to act as a custodian in relation to such of the assets of the trust as they may determine.

(2) For the purposes of this Act a person is a custodian in relation to assets if he undertakes the safe custody of the assets or of any documents or records concerning the assets.

(3) An appointment under this section must be in or evidenced in writing.

(4) This section does not apply to any trust having a custodian trustee or in relation to any assets vested in the official custodian for charities.