Could it possibly be that the "C" is derived from Cavalry??? Most British Tank Regiments, before they became "Armoured" Regiments, were Cavalry Units after all ....

We Canadians have our "8th Canadian Hussars (Princess Louise's)", "Fort Gary Horse (M)" and "Lord Strathcona's Horse (Royal Canadians)". Does any of that sound like there might have been a Cavalry connection ...?

Just a thought......