Well,
Mahogany Bomber, whilst it does as you say 'fill a gap', is it one that actually needs filling? Somehow I never felt the need for a medal saying I've not been Court Martialled (or some other criterion) and that I'd been in for 15+ years. Neither proved difficult for me to achieve, so why should I be given a medal for so doing?
MPN11, 30 years and no medals.