There is nothing to stop you telephoning and asking permission to land out of hours, it will just mean that the usual safetly measures will not be in place. (Fire, radio etc)
Duxford's entry states that everyone has to telephone for PPR and a special briefing and it doesn't matter how many times you have visited previously it makes a lot of sense to do so as they often have their warbirds practising and I for one would not like to get tangled up with them.
London City won't permit '.......... and fights for recreation'.
Only for the last bacon butty
