Holyrood is a commemorative tartan, designed by Alistair Buchan of Lochcarron of Scotland to commemorate the Silver Jubilee of Queen Elizabeth II in 1977. Like a fashion/universal tartan it is for everbody to wear.
Holyrood is also the name of the royal castle in Edinburgh, the Scottish equivalent of Buckingham Palace.
On the pictures below two different kilts are to see. They are 3 yard, ligthweight economy kilts and identical except for the length. One is 21", which, depending on how high or low I wear it, shall be either too short or barely acceptable according to norms. The other one is 22". The vendor was no longer existing Tartan Wear Direct in Glasgow. They are perfect on hot days.