Booking Types - Availability - Min and Max enquiry size
To set up the minimum and the maximum number of people you are happy for a customer to make an enquiry for, go to Settings:
Venues
Select your venue
Booking Types > click on Booking Type you want to set these rules to apply for
Scroll down to 'Availability'
Fill out the Min enquiry size and Max enquiry size columns
Make sure to SAVE the page