I always take a copy of the appropriate CAAP with me (you can download it from the GCAA website) so if I get any rubbish like that I can politely ask the doctor to show me where such tests are required.
I very much take the approach that I'm there for a medical renewal and that is all. Anything outside of that I will get checked out somewhere where my employer doesn't have access to the results, if at all possible. Some doctors are better than others in that regard, some can't seem to get it into their heads that they are not my GP.