It seems the best way to get a bird out of the living room is to let it hurl itself headlong into the window and stun itself.
Then you can pick up said bird and take it back out into the garden.
Of course I wasn’t immediately aware of this method. First I had to go through a voyage of discovery and learn birds don’t like you approaching them hands outstretched; living room furniture is not laid out in a way that is conducive to catching birds; you can never find a fishing net when you need one; a bucket doesn’t make a good net; and a bird is not averse to emptying its bowels when frightened.
Note: one flight into the window at full speed will only partially stun it, but not enough to allow you to pick it up before it’s flapped it’s way across the floor and hidden behind the TV. It takes the second crash before you are able to carefully lift the bird without fear of being flapped or pecked.
After half an hour sitting quietly under a bush the bird will recover enough to fly away.
Either that or the neighbour’s cat got it.