Remote towers might be the answer.
Saab and the Swedish CAA have had a pretty long evaluation of rTWR operations and next year two smaller airports in the north will go operational. One in Australia will also go online next year. It's basically a HD 360 degree view link piped to a remote center where the controller can control multiple airports.
I was thinking this would be ideal for constant-disruption-yet-can't-let-go-and-trust-pilots-with-separation-must-cling-on-to-ancient-operations-and-lacklustre-opening-hours-control-mania that is rampant in Europe and the UK. Gang all the southern airports together using this system for off hours and we could get some true utility out of these black holes at night.
I bet a single ATCO could do Bournemouth, Manston, Shoreham, Lydd, Farnborough, etc after 9pm.