I think I might have seen some scraping by the male this morning!
He's in the nestbox, alone, uttering the same kind of short squeaks I heard yesterday. He is walking around the nestbox, squeaking, stopping to look out every now and then. Twice he squatted, lowering his chest to the gravel, then shuffling forward. Then he stands up again. Once he seemed to mimic the bowing low pose he used yesterday when the female was in the box with him. Mostly though, he is squeaking and peering out of the box (hopefully?! :-)).
This is fascinating. I don't usually start watching the webcams until hatch-watch time, so I've never witnessed the courtship behaviours before!