Fixed!
Just to report back I did two things, one of which has fixed the issue:
I copied the file name from within the properties tab and pasted this into the .json file. There was no change that I could see but did it to ensure 100% name match.
I changed the line in the .json file:
"DisplayStatus": {},
to
"DisplayStatus": {
},
I did that because I saw that how it was in another app so copied it.
One of these two things fixed the issue.