Marketplace
Used the below link by original poster for 15% off: (Juzzy96 - https://www.ozbargain.com.au/node/371281) to book Featherdale Wildlife Park and Luna park tickets last week and it worked!
https://optusperks.experienceoz.com.au/en/sydney/luna-park-s…
Unsure on when it will finish though.
No Luna Park Melbourne unfortunately.