Wow, Trish, I think that is unusual behavior for a Frenchie. I remember an earlier post about a female Frenchie biting a neighbor, but don't remember who posted. It sounds like she is afraid, and when your friend reached out to her she did what she could do to protect herself. I don't know if submitting her was the right thing to do or not, but she allowed the friend the friend to pet her when she was in the safety of your lap. Getting help from a trainer will be good, but that trainer needs to know the Bulldog breed. Does Marg feel threatened when she is away from home? Is she friendly with strangers away from home? Taking her to private training outside her home might be good.