It's possible she's primarily known for her stage work or other artistic endeavors.
To find out more about her work, you could try these resources:
* IMDb: This database is often a good starting point for finding filmographies of actors. You can search for "Miriama McDowell" and see if any results come up.
* New Zealand Theatre Websites: Look for websites specific to New Zealand theatre or performing arts. These may list her credits.
* Social Media: Check if she has a website or social media profiles that might list her past work.
I hope this helps!