According to her website, the Keith Kilt School is where Kathy Lare took her training, both for the traditional knife-pleated kilts and the additional training for military box-pleated ones. And they certify their graduates.

As I see it, the school itself was a response to the need to preserve and perpetuate the art of kiltmaking. (Hmmm... where have we heard those words before?) Oh, yea! Barbara Tewksbury's book was another response to this same need, but it opened the way for "Everyman" and "Everywoman" to to figure out how to make their own kilts. (Your certificate can be minted by The Wizard of BC at his going rate for such things. )