Temi, clients like that are not worth having. If a client does not give you 100% trust in your ability and knowledge then drop them. I rank first page on google for internet marketing consultant, & internet marketing consultancy. I rank first page for google expert (done as a joke)

My client sites rank high for their tems, Yet some potential clients try to tell ME how SEO works. I kill this dead normally by saying " with resepct mister client, here are MY seo credentials (I show him my own and other client rankings), I then say " where is your justification to tell me how to SEO a site?" I point out that on any forum there are people who will give information about how to SEo, But the PROOF of the pudding is in the eating.
I get so many emails and pm's across forums from people who have listened to what I have said acted on it, and seen profits soar (as well as rankings). I am not a guru as I don't go in for all that shmooozing crap, I am just a damn good solid search engine marketer.
Temi have confidence in your own ability and accept that if people want to employ you so THEY can tell YOU what to do, then you don't want them as customers.
Trust me you will feel better about yourself for it.