Some helpful suggestions there and, as ever, a bit of commonsense will be the best way forward.
But Wing or Region have no legal basis to interfere and there is no ‘chain of command’ over the civilian element despite more recent attempts to create one (or at least the impression that there is one. There have been instances where this has occurred and each time Wing/Region has been shown to be wrong. Wing are typically too much like administrative puppets and Region are too steeped in their own interests. Neither have any depth in knowledge of Charity Law and approach this with a sense of assumed control which does not exist in a court of law (hence the pained efforts to keep everything away from the courts - but then who wouldn’t?).
The changes in the current ACP-11 can only be regarded as lawful if they are independently discussed and voted to be adopted by CivCom trustees which some may do and others not. Just issueing a ne ACP-11 from ATC-HQ does not make it a legally enforceable document. In my experience, most CivCom members are not appraised on the extent of their responsibilities and legal obligations Lawfully, the only people who can deal with your chairman are the fellow trustees who have legal authority. Wing have no guardianship role to play and are actually required to act independently in the interest of their own charity.
All that said, your chairman must operate within the adopted constitution which will be the ACP-11 revision that has been last adopted by vote at an AGM. It may be that you have your own constitution which, as long a it maintains the same charitable purposes, is also quite lawful, and necessary through registration if income exceeds the current financial limits.
If your chairman does not call an AGM as per the constitution (which I will assume is one version of APC-11), then fellow trustees should act to promote and even hold one with the chairman invited. The offices of the CivCom are only electable and it would be the responsibility of the other trustees to carry out the election.
If there is not a quorum, then the recruitment of other eligible trustees is a must and cannot just be the WIng Chair and his mate rolled in for the night to make up the numbers for their candidate.
If you as the Chair have concerns regarding professional conflicts (and I do not know what they may be) then you should discuss these with your fellow trustees and have every right as trustees to vary the constitution by which you operate and adopt by vote, again, without change to the charitable objectives as they are. There are trustees who have done this.
If you cannot gain a level of agreement within AGM timescales, then you probably have to stand down and maybe report any specific instances to the police.