Legally not really, practically don't blame you as long as you didn't take too many from the same rootstock or too big a proportion of them.

Legally you cannot dig up the roots but plants by the side of the public highway can be harvested.

Thanks both, for your replies, I may fetch more plants tomorrow. The leaves are now all scrunched up in a small barrel full of water and I'll be watering my plots with resulting liquid shortly.