This is actually called a fly plaid, which is apiece of tartan draped over the left shoulder and attached with a brooch. In days gone by it would have been part of the great kilt of old . The kilt they wold probably would have been wearing is the royal Stewart which can only be worn by royalty and the Queens own pipers and selected regiments with the permission of HRH
Pict of royal tatan, https://pin.it/bhgygdemijiycm . The pictur of the kings
Would have predated this version of fly plaid so would be draped on shoulder

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Best,
Adam[/QUOTE]