I'm quite sure that there is enough blame to go around, Leadbetter included, however this is far from his totally to blame. She's had 2 agents quit because her father is impossible to deal with; when has an agent quit someone with her marketing potential, unless he felt it hopeless.
There was a story, not sure where I saw it, that said one of her parents are almost always within eye shot of her when she is on campus at Stamford .

Seems she might want to fire them before Lead!
Allan