Okay foul!!

Searching by name for MacMillan the STA only coughs up the hunting and the dress.

Going to the alphabetical dropdown there are five or six MacMillan tartans, including a very black one that is listed as a mill tartan #3494.

The MacMillan ancient # 6302 looks like what Marton Mills makes...and so that looks okay as a clan tartan. And there are some other nice looking variations.

Dang ferret was holding out. Probably best to do my STA searches with the alphabet drop down now, just in case.

Still hung up on the red and yellow dress tartan #1723.

Ron