My remarks about the Sikh Highlander have sparked off quite a flurry of comments, not all of them polite.
I repeat that I respect the concession made to Sikh soldiers.
Had I seen the Sikh Guardsman with his low headgear, I would have found it decidedly odd, but since it obviously had official approval, it cannot be faulted.
I still feel that the bonnet badge could have been more to the left, although clearly the position was dictated by the turban’s sharp drop from the high forehead to low around the sides. All the same, I suspect that a larger turban could have been more appropriate (on both the Sikh Highlander and the Sikh Guardsman) – Sikhs in both the Indian and Pakistani armies wear quite large turbans with very fancy accoutrements.
And if the Sikh in question was a visitor to the RRoS, the situation is much more understandable.

On the subject of going regimental, it is only common sense to wear underwear with the kilt in chilly weather (although I endured a fair amount of chill on one occasion), in windy weather, or where it might help reduce the incidence of lice and related pests.
However, having become used to going regimental (in the regiment) I have preference for it where it is suitable and/or acceptable.
Remarks about dirt on the kilt seem to be made in ignorance, since my kilts (when I do wear them) are regularly washed.
Regards,
Mike