This type of thing is such a pain. Had it last year at end of school year dinner for mums and teachers. Some bright spark had idea of doing it with the other Yr 1 class. Thought initially good idea as 2 of my best friends were going. Wrong - other class has a large number of odd bods. The ones who insist on bringing husbands even though it is a girls' night.
We got there early and had a bottle of wine before everyone else arrived. Large table. Most people had a starter and a main or a main and a pudding.
People then started to want to leave at around 10pm and wanted to know "how much do we owe as we only had a salad and a water" - to which I commented loudly "why bloody come out then" to discover person asking question hoerving behind me. She still gives me daggers looks.
We paid for 3 bottles of wine between the 3 of us as we know we are bigger drinkers - people still moaned. It took an hour to sort and finally some of us just put in extra. the girl who was trying to sort it out was mortified.
Never again. This year - our class only. Set menu - priced 2 or 3 courses. Alcohol bill and soft drinks bill separately.