Maybe dorking (because of her short legs) and Sussex.
Those are some random and wild guesses, no way to tell for sure.
I doubt she has Dorking as one pure parent in her background because she would have inherited the 5th toe. But like you said there is no way to know for sure. If she had Dorking say 2 or more generations back this could breed out the 5th toe. I could totally see her having Sussex in her background.