As a new order would the “must” in this one not countermand any previous exemption? Phoenix vehicles count as service anyway so the ACO will just have to shell out for them!
Para 2 states private vehicles can be used for section 1 weapons (No8 and cadet target rifle). Para 4 refers to section 5 weapons but I’m not sure what they are.
Firearms (Amendment) Act 1988 Wikipedia Act
From a Cadet Forces side of things this is the L98A2 or L86A2, but I’m no expert, hopefully this will be further amended/clarified to include a list of Section 1 & Section 5 Firearms for Cadet Forces.
This certainly makes life easier from 4 vehicles to no more than 2 
now just to get enough safety supervisors to the range…
I think they have gone with Section 1 and Section 5 to make things easier. Section 5 firearms are the L98A2 and the L86A2, simply put they are weapons that are totally banned in the civilian shooting world. Section 1 is all of our target rifles.
wrt the requirement to use ‘military’ vehicles, in the CCF this is covered by the Headmaster issuing authority for the school vehicle to be used for CCF activities. When the new guidance came out last week I explicitly queried if this still applied and it does. This form is contained in LFSO2901, ‘Security of Cadet Forces’.
No idea if that helps the ATC as you aren’t Land, of course; perhaps you can get authority from Wg Cdr/WExO or perhaps the vehicle owner (CivComm?) to use it for cadet activities. But remember the head teacher is in the CoC, the CivComm isn’t.
Is there any more news on 1WW & 3WW shooting at St Athan? Have cadets been able to go else where to shoot?