To get an insight into relative intellectual levels of different kinds of soldier in the UK Armed Forces in the '60s, at least, look no further than how artillery support was provided for the then new concept of the "Commando Carriers", old aircraft carriers converted to carry a Commando (ie battalion strength) with artillery support, to be landed ashore to extinguish brush fire rebellions in the remaining bits of the British Empire.
In preparation for the commissioning of the two carriers (Albion and Bulwark) the Navy decided to resurrect the old Royal Marine Artillery and form a 6-gun battery for each carrier to complete the Commando battle group. Unfortunately, it proved impossible to find any Marines clever enough to learn how to work out the sometimes quite complex arithmetic for surveying gun positions, then providing indirect fire support without actually killing the grunts in front. After a year or two, with the commissioning looming, a lateral thinker in the MoD suggested that a Royal Artillery Field Regiment should be ordered to go to Lympstone RMCTC and pass the Commando course, shortened to keep all the physical training activities and tests but dropping the basic soldier training. Since it was already located in the Citadel in Plymouth, 29 Field Regt RA was selected to do this. At the time the regiment was split between Kuwait and the Yemen border in Aden Protectorate, but all quickly returned to the UK . With one exception every single member (ie 500+) of the regiment passed the same Commando course tests as the RM recruits, in batches over the next 3-4 months, the regiment was re-equipped with 105mm light howitzers of Italian design, and was thus able to join in the commissioning cruise of HMS Bulwark, practising landings on the South Coast, mainly in the Lulworth Cove area. The RNAS squadron on board had the new Wessex to contend with; among other learning curves confusion about the location of the hook release button and the PTT button, different from the Whirwinds they had before, led to guns and lightweight Landrovers inadvertently being released. (You know; P2 to P1, "Wossa time then?"; P1 to P2 "Half past sev......oh ****".)
And so 29 Commando Regiment RA was born; a monument to lateral thinking.