Now for you opinions...would the physician have invited me back if he didn't think I stood a chance at gaining a Class 1?
Since there are many benign, non-progressive conditions that can cause scotomata, there's no reason why he shouldn't invite you back. As long as it's nothing serious and it isn't progressive, he can certainly sign you off for a Class 1, and chances are excellent that it's nothing bad.
I've done a bit of research and there are several nasty illnesses associated with blind spots on the retina, but I'd rather not think about these too much (I have a habit of scaring myself about these things and making my life in the meantime a misery) until I have an official answer.
Sounds like you missed all the harmless conditions that can cause blind spots during your research. It could just be a floater near the retina, and that is typically harmless and not progressive. You won't know until an ophthalmologist looks at it carefully, but panic is premature.
One of my relatives had a spot on his macula that looks an awful lot like macular degeneration to his regular doctor, but careful evaluation by an ophthalmologist revealed that it wasn't that at all—probably just an anomaly that had been present for years, or even since birth.
Despite maybe being rare, is it possible to be born with or naturally have a static blind spot on the retina, without it being associated with something more sinister?
Yes, although it would have shown up in visual field tests before (unless this is the first time you've had such a test).
For example, everyone has a rather large blind spot in both eyes where the optic nerve enters the eye, but most people are totally unaware of it unless they do a specific experiment that reveals its presence. So you could have some anomaly for ages if you are never in a situation that makes it apparent.
For what it's worth I have never noticed anything wrong with this eye, never felt anything unusual and having worn glasses for 11 years I've always attended my annual check-ups at the opticians where again, nothing unusual has been spotted.
At least in the U.S., an optician is not an ophthalmologist; many people go only to opticians without realizing that they don't know how to look for everything. A good examination by an ophthalmologist is a wise idea now and again, and it sounds like it would be a good time for you to get such an exam right now.
If you haven't seen anything before, either there was nothing there, or it was something so non-progressive and minor that you just never noticed.
In any case, see an ophthalmologist; it's unlikely to be anything serious, but since serious things can be really serious, you should not delay. In the meantime, don't panic!