I would like to happily declare our newly built nestbox and camera put up today. To all blue tits, great tits, tree sparrows, and birds that can squeeze through, you are most welcome to come and use it.
Many thanks to all who helped with advice.
The box is located on the wall of the house, under the eaves. It faces south-east, and because of the wall next to it, there is no sun on the box past midday. The box gets virtually no cold wind blowing against it, and is sheltered from the rain due to the overhang of the eaves.
First pic of the inside. As you expected - it's empty !