Good evening,
As far as I recall Max, all cavalry regt's who wore landyards wore them on the left. Video of 5 DG's final parade in the 90s show the landyard on the left in SDs. No landyard with blues but aiglettes on left in ceremonial dress.
Have tried to find pictures from the early part of the century showing them in drill order but no luck.
Just for interest there used to be 3 regts with drum horses but as 2 of them amalgamated in 93. Now only 2 although for a short time QRH had both of them until I believe 1 was sent into retirement.
John915