What if nobody in Gisborne does this?
Then the honest answer is that it comes from out of the region, and the quote should say so with the travel in it. NovaPay asks locally first and widens rather than pretending the choice is bigger than it is.
What is a minimum spend?
Most venues hold a room against a dollar figure rather than a hire fee, so you commit to spending it whether or not you do. Ask for it in writing along with what counts towards it.
How far ahead should I book?
For November and December, months. Venues fill for work functions well before people start organising them. Any other time of year, a few weeks is usually enough.
Can we have the place to ourselves?
Exclusive hire is usually possible and usually costs more than a reserved area. Say which you want, because a quote for one is not a quote for the other.
What about dietary requirements?
Give numbers rather than a note on the night. Say the requirements in your request and the set menus that come back will already work for everyone.