Salgado Investigation’s Marketing Questionnaire

I am currently doing some market research into how and why solicitors choose the process servers that they do. I am trying to get to know my primary customers better. I have composed a list of questions which would really help me out knowing the answers.

In a typical firm i.e. your firm;

Who is the decision maker?
How does that person search for their process server? Ask the legal assistant secretary? Google? Consult list of providers?
What makes them choose one over another? Price, USP? Special Offer?
Are solicitors open to cold calls?
Are solicitors open to marketing emails?
Are solicitors open to marketing letters?
Do you think I should ask other questions on this questionnaire or do you have any marketing advice?
Do you know of any internet forums that Solicitors typically visit?