With regard to management staff members who, irrespective of whether they were in an acting capacity or not, left the Passenger Rail Agency of South Africa since 1 April 2018 either due to (a) termination, (b) resignation, (c) suspension or (d) any other reason, (i) what number of vacancies occurred in each instance, (ii) what were the reasons for them leaving in each case, (iii) what processes were followed in each case and (iv) what were the salary scales in each case?