OK, but can you clarify what you mean by:
"Give each file system a different volume label when you build the ISO and then see which one gets shown by each operating system. If they both show the same one, it’s must be down to the way it’s parsing the descriptors of said file system."
What do you mean "each filesystem"? I used ImgBurn to make an ISO out of an img file containing files and folders. The img file has an NTFS filesystem. The ISO file I made from that using ImgBurn has a UDF filesystem. And this ISO file does not display the hidden files and folders when I open it in Ubuntu with Disk Image Mounter (DIM).
I also remade the ISO file in Ubuntu using mkisofs using this command:
mkisofs -v -J -l -R -V "ISO-Label" -iso-level 4 -o output-file.iso /img/file/mount/point
This ISO does show the hidden files and folders in Ubuntu when I use DIM and in Windows also. The filesystem of this new ISO file is CDFS. The img file and the two ISO files all have different "labels". When I right click on the hidden files and folders as they are showing in the ISO file in Windows I see from the properties that the "hidden" checkbox is ticked. Yet in either OS I try to open the ISO files in I always have "Show hidden files" enabled.
I have to use this command from Ubuntu to make the first ISO file (UDF filesystem) display its hidden files and folders in Ubuntu:
sudo mount -t udf -o loop,unhide /media/my/file.iso /mnt/ISOFileContents
So maybe Ubuntu does not understand the UDF filesystem properly and that was the wrong setting to choose when building the ISO file in ImgBurn? I'm still googling and trying things but welcome any more ideas!
Maybe DIM does not mount UDF filesystems properly to respect the hidden file attribute? Hence the only way to make them show all their files properly is via mounting manually... or use different settings in ImgBurn. I'm just thinking out loud.
Cheers.