Thank you for the welcome
Love the pig idea, but it's a no go for me.
I've been doing more research and it seems that, unless they ate loads of fallen acorns and oak leaves, they should be fine. Extra precautions when they fall and a change in where their hard standing and shelter will go, will help.
It's amazing how different the information is from source to source, plus much seems to come from the USA rather than being UK specific. It was one of the few UK specific books that brought up oak trees and sent me in a spin.
Next step is getting my head around the movement, herd number and record keeping paperwork.