The Blue tits started nesting in March in the box at the bottom of my garden but unfortunately a nearby fence blew down in strong winds and they deserted (as they did last year). But good news there are now a pair if Great Tits in residence! Trouble is, the box is right next to my sun deck, so no sunbathing for me this spring!
I'd rather the great tits than a tan

Well, that comment is hard to follow.
Our garden is sunny at one end in the morning and sunny at the other in the afternoon. No afternoon sunbathing for the next few weeks as we have both blue tits and robins nesting at the afternoon end!
Congratulations on the nesting box success!
I have a pair of Black-capped Chickadees (a US version of tits, being in the Parus family), and have no idea where they are nesting! But the nest is close by...
Kingfisher