Link to Fern societies. http://www.burkesbackyard.com.au/fact-sheets/people-places/fern-collector/

I’m not a fern expert, but check out the narrow swordfern (Nephrolepis cordifolia) and see if you have a match. You could also try to get in touch with the experts on the second included link for further help. Best wishes! https://keyserver.lucidcentral.org/weeds/data/media/Html/nephrolepis_cordifolia.htm