I last saw the old queen on Sept 13th and then on my weekly hive inspections since I thought i was queenless (the old queen was so obvious, huge and amber coloured).
Yes. I have looked back at your posts since joining the forum. At these inspections, when you were clearly looking for the queen, what was the first time there were no eggs, no open brood, no capped brood?
Draw yourself a time line. The queen cell, if you were inspecting every week, would have been there for two inspections at least.
Usually at this time of the year the queens will start laying promptly on getting mated. If they do not start laying soon after suitable mating weather, they are likely not mated.
Being possibly Q- for five weeks now and just now found with another queen in residence with no signs of eggs, I have considerable doubts as to the fecundity of the current queen.
But the weather may have been warm enough for mating flights at times. Of course she could have been a supercedure queen long before September the 13th. There lies another conundrum...