TIO, and THAT is the bone of contention. I think the same pressure was applied to coffee bars etc elsewhere.
At Coningsby the NAAFI van went tango uniform and NAAFI stopped providing the service. An enterprising local bought a small white van, stocked up at the butchers outside camp and then did the rounds with a suitable markup. She made a profit.
The difference is NAAFI was trying to use the familiar WW2 style mobile canteen that probably cost squillions to run.