Tar, Brush....
Chug, you seem intent to talk about indenpendence, and BOIs etc, in the context of the MOD, but as pointed out above, the Services work differently, with the RN and AAC having a separate Acc Investigation function, outwith the HQ. Perhaps before pushing for an external solution, we should look at where better practice may be found internally.
Don't tar the whole MOD by how the RAF do business.