Last year, we replaced one of our bird boxes. Though blue tits expressed great interest in it, they showed just as much in the broken one we’d removed but left nearby.
As far as we know a blue tit pair started a nest this year but abandoned it before laying eggs.
Today, we have moved this bird box and the one we made to encourage robins to nest in my Potting Shed. They are now more sheltered from the wind, higher up than previously, safe from cats, and close to where the bird feeders will hang,