Pistons, I think you misunderstand the current UK system. There is no requirement to operate to military airworthiness rather than civil.
Airworthiness is airworthiness and the UK military system recognises the civil system in its entirety. As a result we have military fleets run in accordance with civilian standards and overseen by the civilian regulators. This includes any supporting elements including civilian training and licences for military maintenance personnel.
Adopting civilian airworthiness systems is seen by the UK MoD as cheaper and lower risk. Pure military airworthiness systems are only used when no relevant or appropriate civilian system exists.