Every alcohol sale must be covered by a premises licence or a Temporary Event Notice (TEN). Ask the owner first, because a unit whose premises licence already covers your sales needs no TEN. A TEN also covers entertainment such as music and dancing, and hot food or drink served between 11pm and 5am.
You give a TEN to the council as an individual aged 18 or over, at least 10 clear working days before the event. If your pop-up runs longer or larger than a TEN allows, apply for a premises licence instead.
Temporary Event Notice (TEN)
How to give a TEN, and what happens if the police or environmental health object.