Thanks for the info and photos Jeff and Gizmo. Some interesting looking machines in those photos.
Yeah I figured that Villiers might be hard to get going. I tested for spark on the Briggs today and got nothing. So I think I will just find the missing bits for them over time, but not try to renovate them or get them going. I'll just leave them the way they are.
Funny thing, I showed the oldest one to an elderly relative and he said he could remember pulling the starter on one of those until his fingers were blistered. So they clearly had a reputation.