Tim, I ask the piper where he bought his kilt, a shop in Edinburgh near the castle, didn't say which.
Gray, I suspect this shop is the same one from which I bought my Saltire kilt, namely 'Colin of Edinburgh' (formerly The Scottish Store) at the top end of Johnson Terrace. However, since this tartan is restricted (in the weaving, not the wearing!) the kilts are made up by only one firm of kiltmakers as far as I know. These kilts are now offered by many other kiltmakers and Highland Dress outfitters across Scotland who presumably act as agents for the weavers.

It is an intriguing weave across a somewhat simple tartan, and the Saltire marking appears only on the outward facing side of each pleat - as the pleats swing open the Saltire becomes fragmented, for want of a better word! If the design were to be woven continuously across the fabric, the Saltire would have jagged edges and would be most unattractive. Personally, I do not consider this kilt to be a flag at all, and so I have no compunction in wearing it.