I have received a very helpful reply from RNZYS. They have confirmed that they are setting up individual Custom races and that they are manually collating the results for a series. They are considering using 'Sail Ranks' for the results.
I have also established that if you try to create an event using '+Create >Event', at the top of the Club screen, you are only given the option of creating a 'VOR Inshore Race' , which then shows up on the Calendar but not on the Club's 'Event' section. It also gives you no means of editing an event.
However, if you use 'Create Event, in the middle of the Club screen, the Event shows up on both the Calendar and the Club's 'Event' section and is editable. Ticking the RSVP box when you set up the Event, creates a box which allows members to indicate whether they 'Are going' 'Maybe' or 'Decline'.