The F1Scottish Court ServiceF1 in the case of the office of any sheriff clerk or sheriff clerk depute, and the Lord Advocate in the case of the office of any procurator fiscal or procurator fiscal depute, F2. . ., may from time to time, having regard to the amount of business to be performed, determine that such office shall be a whole-time office; and no person appointed to any such office under this Act (in this Act referred to as a whole-time officer) shall engage directly or indirectly in practice as a law agent or carry on any employment of such a nature as will, in the opinion of the F1Scottish Court ServiceF1 or of the Lord Advocate as the case may be, interfere with the due discharge of the duties of his office.