Do any channels still close down at night?
Depends what you mean by 'close down'. Gone are the days when a channel can end programmes for the night and switch off their transmitters, it's all multiplexed data streams. There are channels on DTT
whose bits get turned off and used for something else.
If you mean they stop showing programmes then BBC2, BBC4, Cbeebies and CBBC all stop for either a caption or loop. A lot of channels show tellyshopping overnight, they're essentially a different channel as there's no branding and are kept seperate from the traditional programmes