In fact, thinking about it, the already issued RAF 'Valedictory Certificate', or previous to 2007 teh 'Valedictory Letter', should show that entitlement and so there would be no need to issue anything - just change the policy to include this. It would need to prove the same length of qualifying service.
No cost to MoD, entitlement officially given to veterans and if they wish they may purchase and wear the 'Long Gong' as Officers like those that are currently serving.
LJ