The best venues for small events are intimate and special. Think of a private dinner in a listed building. Or a workshop in an artist's studio. A strategy session on a boat works too. Or a wine tasting at a local chef's home.
Avoid halls that are too large and feel empty. The sweet spot is a space that is just big enough. The group fills the room without it getting crowded.
More venue tips in our article on organising a small-scale event.