Mr Shepherd is so good at what he does and plays Sir Walter who is basically a child

I think this says something about the Mr Wentworth's character. He is aware that people don't steal apples for fun but out of necessity. Mr Shepherd obviously thinks the person should be punished

Sir Walter is asking for the ridiculous - that people can stay in his home but not be allowed in the grounds. Mr Shepherd is very diplomatically stating that there is a standard set of usage for tenants (kinda like tenants rights).

Sounds like father and daughter are working together on her plot to seduce Sir Walter

I take this to mean that he wants to get paid too and he's probably being chased by Sir Walters creditors

He's a master manipulator, you can see where his daughter Mrs Clay learnt it - good for them, they have no power in this situation. Sir Walter requires expert handling and he is handled by everyone around him almost like a child