Hi Swift. I have deep soffits so made the shoebox type as found on https://www.bristolswifts.co.uk/swift-nest-box-design/
This is one of mine (speaker removed from holder after Swifts were established), I had to paint in Farrow and Ball colours before my wife allowed installation
Still here this morning... I'm biting my nails a little!
We have better weather at the moment so I'm hoping they take advantage...
I can't believe I'm actually wishing them to go