An interesting question. I know Major Donald Gilchrist in his book Castle Commando mentions a Pipe Major being at the Station on his arrival at Spean Bridge in 1942. Where there is a Pipe Major there should be a Pipe Band. Also Major Jimmy Dunning mentions in his book the Pipe Band as you say doubling up as the Demonstration Troop in early 1943. The gallery has several photos of the CBTC Pipes and Drums and will give you an idea of their strength but I have not seen any official document.
The formal one at Achnacarry with Lt Col Vaughan is probably the best to go on, and seems to have 6 drummers (side, bass and tenor) and 8 pipers, if you include the Pipe Major.
Pete Rogers, son of LSgt Joe Rogers MM & nephew of TSM Ken McAllister. Both No2 Commando.
God and the Soldier, all men adore, In time of danger and not before.
When the danger is passed and all things righted, God is forgotten, and the Soldier slighted.