If I could just find the plant badge in a nice silk version so it won't wither.

IRIC, the plant badge was worn in the cap as a means of identifying fellow clansmen before the clan tartan system came into being.

Graham, I also have one of those green balmorals. They are a great combination of quality and price. With cooler weather here I like to wear it (generally w/o a cap badge) out and about until temperatures dictate something more robust. And it works very well without the kilt (for those of us who haven't yet eschewed thr trousered look).