Well, ok, since you insist; though the reason I didn't bother was because your questions are still very obviously rhetorical, and based on a false dichotomy. My interest in this is clearly explained in my first post, which also answers the questions you keep asking, so I assume you haven't read it...
I am a patient not a dentist. Of course if you are the sort of person who thinks that only 'expert opinion' is worth anything, then you will want to dismiss mine. But my background is in patient and public experience, so am used to the idea that clinicians are not always right, or the only people worth listening to. I'm not very familiar with the commissioning framework for dentistry, but I'd guess that as in the rest of the NHS, patient experience - and specifically patient reported outcomes - are becoming increasingly important. In hospitals round the country, clinicians are discovering that if they dismiss patients' views, their 'PROM' scores will be low, and their payments will be correspondingly lower, and contracts will be lost. If this reality hasn't hit dentistry yet, it will so soon. So if patients tell you they don't like dental dams, and you ignore them, you will be foolish.
In this case, it's not just patients who don't like dental dams, but also the majority of dental practitioners. To repeat figures you are keen to ignore, 80% of British dentists do not use dams, and 60% have never used them.
See, that's why I didn't answer you, twice: it really is pretty boring for most people, and doesn't answer the OP's original concerns. Sorry Hetty. :)
For what it's worth Hetty, I think you should ask for whatever you prefer. If you want your dentist to use a dam, ask. If you don't, that's fine. The dentists here who say they are 'essential' are in a minority, and most UK dentists don't use them. But you should ask for whatever feels right for you.
Good luck tomorrow! :)