Hii Richard, these unpredictable things happen and yes its frustrating but, its only a tiny mark, perhaps on the coating. Try not to look at the objective
its way more satisfying looking through it. I doubt anyone could look through your telescope and say, Richard, I think you have a tiny obstruction causing a barely perceptible degree of light scattering. And, think of all those newtonians, cassegrains, richey chretiens, and maksutovs etc with secondary mirror obstructions (some are huge) and the thousands of proud owners who don't notice any image degradation. They still manage to give quite nice images
Enjoy your magnificent telescope. Mark