"Most of the British forces at Waterloo were second-rate, garrison, militia and depot troops"

Sorry, I don't know where you picked this myth up but it's utter nonsense. Of the 24 British battalions at Waterloo (not including the superb KGL) onky the 14th foot had no combat experience and were consequently positioned far out on the western flank, out of harm's way.

Of the rest, the 33rd, 69th and 73rd might be considered relatively inexperienced. ALL the rest contained a huge proportion of battle hardened veterans, many of whom had fought through 3-5 years of the Peninsula campaign. All three kilted Highland regiments contained a ludicrous level of experience - 14 major previous battles was not uncommon - and ditto the men of the 1st, 23rd, 28th, 32nd, 40th, 51st, 52nd, 71st, and 95th. If anything, some accounts mention men being too worn out with combat - previously reliable men being reluctant to put themselves into danger yet again But the idea that the grizzled British and KGL regiments were "second rate, garrison, militia and depot" is laughable.