I can't speak for 58 Sqn and 6FP today,
but there was a small war, in Oman, in the '70s when 51, 2 and 15 Sqn RAF Regiment were quite busy, as were the Royal Engineers, the artillery, several others and the "British Army Training Team" (SAS).
They took casualties and had quite a few nasty engagements, but when they came home there was not even a flicker of recognition. It was a "secret war" because of the then political position.
I may be wrong, but it may be that 58 and 6 were proud to parade in St Andrews.