Good news! I’ve sorted it and thought I would post an update for anyone else who experiences this issue:
I followed the steps to reflash the SD and I am now able to see the Organelle in AP mode and have set it up with my own WIFI network and downloaded a bunch of patches, so I’m well happy.
A few things to note:
I couldn’t directly reflash, I had to reformat the SD first - I used the Mac OS Disk Utility and reformatted as a MS DOS container.
Then when I downloaded the Org OS 4 the Mac OS, Big Sur, automatically unzips once downloaded so I didn’t need to use the Unarchiver app.
I was then able to use Etcher to burn the ISO to the SD.
I’m already buzzing with creative ideas with these additional patches and will be using much more of the Organelle on future Hawksmoor recordings.
Thanks for your help and support and I’m really pleased we got there in the end!