Thank you for being here @LouisJenkinsCS !
I do not have a timeline for you but I did want to let you know that our team is definitely still looking into this feature.
Mark helpful posts with Accept as Solution to help other users locate important info. Don't forget to give Kudos for great content!
I don't think that GitHub Community, which runs on the Lithium Community platform, has support for Markdown, let alone GitHub Flavoured Markdown. I know that there is a certain level of modification possible with Lithium Community based on some other community instances, but I'm not sure if a completely new text formatting processor is possible without special modifications.
@FanrayMedia Github says, "We are absolutely committed to open source and did investigate open source tools, but they didn’t provide the feature set that we needed for this forum."