Not quite true, probably best to check the source doc first maybe?
MAFL clearly states:
5. The following persons may place an officer in arrest:
(a) an officer of the Royal Air Force of superior rank;
(b) an officer of the Royal Air Force of any rank, when the officer to be placed in arrest is engaged in a quarrel or disorder.
(c) a provost officer, or any officer, warrant officer, non-commissioned officer or rating legally exercising authority under a provost officer or on his behalf,
provided that if the arrest is to be effected by a warrant officer, non-commissioned officer or rating, such arrest must be under the orders of an officer, and the
order to arrest should preferably be in writing;
So, as you can see, permission is required before an NCO Copper arrests an officer (at present).