Something I will always associate with William Britain's is the sentry-box. Probably when I was a kid I thought soldiers lived in them thanks to the toys I owned. When did they come into practice? You see stone ones that are round on fortresses but wooden ones? This Prussian example from c1720 is one of the earliest I've seen. Search Anne Brown collection for sentry-box. It would be a nice touch if 18thc reenactment groups had these as props - be useful at a garrison type event. Probably impractical to cart around unless you could flat pack them. You can get ones made of wood for your garden.
Luke Kelly and the Dubliners perform the traditional song 'Gentleman soldier' a song that features a sentry-box tryst.
Image search sentry-box