It is NOT OK to make social chats on air band frequency even if the relevant ATC/FIS/Radio station is closed. Every time you press the transmit button you block further communication.
It is recommended to be in communication with some service provider.
Blind calls can be useful if within an ATZ i.e. following a circuit pattern, arrival or departure.
If Brize or Shawbury or ... are not responding, then contact London Information, London will be able to help and advise who to call.
Remember it is in your own interest to be in contact with some service provider, it is for your safety/benefit!!!!!