The female then spent quite a long time taking stock of their potential new home.
In this shot you can compare the size of her black patch and the stripe down her front with that shown on the male earlier - clearly the patch is smaller and the stripe is thinner.
At the time, we thought she was taking a long time to look around. What we hadn't realised was how desperate these great tits were to find a new home.
We suddenly realised that the male was watching anxiously from outside the box - did she like the home he had found for her?
A mere twelve minutes later we had our answer - in she flew with a huge beakful of moss!
Suddenly we saw that great tit females do nesting wriggles too! I suppose we shouldn't be surprised to see so much common behaviour between the two species.
Once this bird has made her mind up, there's no stopping her. She was coming and going for most of the rest of the day. This shot was taken shortly before four o'clock and already she has nearly covered the floor of the nest box.
At the end of the day, this is what the box looked like.
Poor Carlos. Would he try to roost again tonight? But no - we saw no sign of him. We only hope that we are right in thinking that he and Megan have a nearly completed nest somewhere else!
Just to remind you in case in the excitement you had forgotten - here is Kelly settling down to sleep on her nest.