For the avoidance of doubt, things would almost certainly had gone better had I not failed, for whatever reason, to see the other aircraft, for which I apologise.
The question I was trying to ask was: "when I became aware of the other aircraft, after having crossed the hold line, was there any point in my stopping rather than proceeding to take off?"
The clear answer I'm hearing is "no, an occupied runway is an occupied runway at an A/G airfield just like it is at an ATC airfield, so if you had stopped they couldn't, shouldn't and wouldn't have landed anyway".
That wasn't the impression I got from the instructor. I got the impression that he had wanted me to stop, on the taxiway but past the hold line, so that he could land anyway.