Further to the comments and book titles I referred to in the previous post, your enquirer might want to make contact with Angie Goodloe and Henriette Kress, both are practicing herbalists with young children. Angie's herbal blog ishttp://herbalistpath.blogspot.com/.
She lives near Portland, Oregon. Henriette Kress' site ishttp://www.henriettesherbal.com/
and she also runs an email discussion list about herbs with international members. Henriette lives in Finland and trained in the US with Michael Moore. I wish I could give you links to some British herbalists with young children, but I don't have any. Zoe Hawes works with children and you will have met her last Saturday.