what evidence suggest that pips benefactor is miss havisham

The most obvious thought is that Miss Havisham is the benefactor because Pip is visiting Estella and "playing" with her. It seems that perhaps she is paying because he is providing a service.

The fact that she helped him as a youth and was responsible for bringing him into her home. His family was aptly rewarded and suddenly he has the chance to go to London and become a gentleman of means. Pip doesn't know anyone else who could have done this for him............... thus, it had to be her.

-Miss. H is the only rich person Pip knows.

-Pip thought that Jaggers was employed by Miss Havisham.

-Pip thought Miss. H was giving him money to make him worthy of Estella'a affections.

Miss H knew all the details of pips case. Also Jaggers in employed by Miss H as her lawyer.