Update: I heard peeping yesterday and assumed it was coming from the egg on day 22. Just looked in the bator this morning and realised it must actually have been the day 20 egg that was making the noises, as it has now pipped. Nothing yet from the older egg that is now on day 23. That's the egg I thought was looking good and the one that's just pipped was the one I was feeling a bit iffy about because of the huge air cell.
That just shows how much I know, eh?
I don't want to leave that other egg in there too long as I need to reduce the humidity as soon as I can for the other eggs that are now on day, um... Wait a minute. Day 10. Had to go check my notebook there. So as soon as the one that's just pipped has hatched, I'm going to float that other one and see what's what.
Edit: 90 minutes later: Wow, it's hatched already! Once it started zipping it blasted the whole way round in about ten minutes! It's wriggling around drying off now and peeping like mad. I floated the other one and - nothing. Candled really carefully, tapped the shell and looked for any movement and - nothing. Cracked the shell at the fat end and yup, it was definitely dead. On closer inspection, it was perfectly formed but not quite fully developed so I think it must have quit a few days ago. Oh well...
So I've grabbed out the extra water trays and I can now get my humidity back down to normal for the other six eggs in there.
I've also got another eight eggs I've collected in the last ten days or so and now I'm wondering if I should extend the 'experiment' a bit and set them too...