Validity of certain transactions and documents 39 Validity of certain transactions entered into by trustees (1) Subsection (2) applies where— 20 (a) the trustees enter into an onerous transaction with any person, and (b) the transaction is one under which the trustees purport to exercise, in relation to the trust property, or to any part of the trust property, a power under section 13(1) or 16(1) whether the power derives from the trust deed or is implied by those sections. 25 (2) The validity of the transaction, and of any title acquired under the transaction by the second party, are not challengeable by that or any other person on the ground that— (a) the exercise of the power is at variance with the terms or purposes of the trust, or (b) on the part of the trustees, there has been some procedural irregularity or omission. 30 (3) Except that, if the trustees are acting under the supervision of the accountant...