Hello Genie. I do not know the answere to your question so I had a look at the gravestone inscriptions that I have.
There is only one Farrar stone and that is for a Rev Wesley Farrar at Lanchester,so I do not think it would have anything to do with him.
I think you would get more responce if you reposted the question using a new subject heading, suggest:-
"Origins of the name "Farrar's Arms, Crook"
Adam