The binding legal principles are: (1) Disqualification under section 372(f) of the Companies Act arises from the fact of conviction and sentence to imprisonment (whether suspended or not) or a fine exceeding R20 for specified offences including theft and fraud, regardless of who actually committed the offence or subsequent expungement. (2) The Master's compilation and maintenance of a panel of approved liquidators and trustees, and decisions to add or remove persons from it, constitute administrative action under PAJA as they implement statutory appointment powers, have direct external legal effect, and adversely affect rights. (3) A subsequent unchallenged administrative decision on the same essential issue (here, the appellant's suitability for appointment) that remains binding renders nugatory challenges to earlier related decisions. (4) Liquidators owe duties of absolute honesty, transparency, independence and accountability to the Master, creditors and companies in liquidation; conflicts of interest and dishonesty justify removal under section 379 of the Companies Act. (5) The Master's powers under section 381 to enquire into liquidators' conduct are essential supervisory tools and liquidators have a corresponding duty to cooperate and respond to legitimate enquiries.