I would guess NAAFI' s problem was the rapid shrinking of front-line(NAAFI front-line) services but fixed costs of HQ and logistics. Not just front-line but I think NAAFI provided food to Catering Sqn.
I remember NAAFI branded goods like tins of coffee beans were Good value. Still have some empty tins in my garage. Put them on Antiques Road Show if they don't sell on eBay.