The blue tit in the camera box laid her first egg on May the 4th (she must be a Star Wars fan) and the last one on the 9th so there are six eggs. The smaller than average clutch is consistent with the late laying date (because of the cold weather). The BTO website quotes a blue tit incubation period of 13-15 days but doesn't say whether that is from the first or the last egg. Over the last six years in this box hatching has been 18-25 days after the first egg and 10-19 days after the last egg. The fledging time has been much more consistent at 18 or 19 days.
The male has regularly been bringing in food for his mate, usually St Mark's flies or caterpillars.
I'll put another post here when the eggs hatch but more frequent updates will appear on the "Nestbox camera 2016" page accessed via the tab above.