Yes, that did the trick. I used your idea in many different tests that I have done and basically added the second of the following two lines and that seemed to do the trick.
Thank you!
...
Plane Surface(1) = {1};
Physical Surface(2) = {1};
Great! You're welcome.
So you didn't need the Physical Line… I wonder if my warning about those being required all round were wrong or outdated… Let me check.