One of the biggest regrets of my flying career was not having the balls to report a serious 'cross cockpit gradient' that existed between myself and an instructor.
[EDITED: If you haven't read it by now, too late... this was for PPruner2003's benefit. The content of this text made myself and the other party identifable by our mutual aquainances - so it is time to hide again
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Approach the CFI or Boss and explain the situation and/or write a letter. It doesn't have to be written in terms that the chap will lose his job, but you should say that you feel uncomfortable with that particular instructor. You can separately explain that you have been unimpressed with the club as a whole...