it came to me in a flash and I will share my brainwave with all my kilted friends !!!

sticky bcked "velcro" and tiny square stuck to the rear of your jacket lapel -invisible at all times !
then a tiny square on the end of the plaid and it stays put no matter what!!
I dont naormally wear my plaid but im doing some Pipeing in June and the plaid looks good for pipeing!!