I think a conversation with the council is probably the best way ahead.
Yep, environmental deal with it these days, but might be trading standards.
These are the licensing objectives:
prevention of crime and disorder
prevention of public nuisance
public safety
protection of children from harm
If it’s for some occasional street party, then I guess the licence officer might consider the views of your neighbours and without doubt what measures you’ll have in place to prevent sales to under age, proxy sales and people who’ve had too much to drink. Most licensed premises these days run a Prove It policy, where if you appear 21/25yo or under, you have to prove you are 18 or over.