You have the right to give the council a Temporary Event Notice to use any piece of land or property for the sale of alcohol, provided certian limitations have not been exceeded. These are:-
1. It has not been used for more than 12 times in a year,
2. It has not been used for more than 15 days in a year,
3. The event will not last for more than 4 days
4. You have not given more than 5 such notices in total in a year.
It will cost 23 UKP and no one can object except the Police, on crime and disorder grounds, which is unlikely in the circumstances.
There is a form filling requirement which your council licensing department can tell you about and you have to give a copy to the police when you submit it. You must give at least ten working days notice of the event. Best to give lots more if you can. Remember, you cannot be refused this unless the police interfere If they do, post agai and I will tell you how to get past it.