JSON Pattrstorage, Presets + Standalones.

I know this has been covered many times here - but I'm up against a somewhat confusing situation.
I've done everything I can try that's been covered in threads I've found, but I've still not come up with a solution.
I've even tried making some very basic tests to try first, but have had no joy.

So it is nice and clear, all I need to do is load a bunch of data from a json (previously saved from a patch using pattrstorage) and have it populate out a bunch of presets in a preset object (and of course, work with the pattrstorage!) And I need it to happen inside a standalone.

I do not need to be able to SAVE into the JSON at this stage (inside the standalone) - would love to at a later date, but that is not as important.
What I have done / tried. The pattrstorage looks like this:

pattrstorage GenS @savemode 3 @autorestore 0 @fileusagemode 1

I've tried both ;max sendapppath (and I get the correct answer) or just a simple read (where I manually show it where GenS.json is).
The best result I've got is from the read command - where I can see all the data in the standalone using a storagewindow, but it does not populate out the presets (which it does when I'm on both a mac or pc doing the development.)

I have tried putting the GenS.json in various places (root of the created app folder - so alongside the exe, in a /contents/ folder inside the app folder... even back in the cycling'74 folder for kicks. )
None of this gets me any closer.

I feel like I've followed the following advice (which seems to help most people out) to the letter, but it doesn't help :

1) Set "fileusagemode" = 1, for patternstorage. (also choose a proper "savemode", start with 1 for testing purpouses)

2) If you have already created a .json just move it to another place then reload the .maxpat, it has to load with all pressets blank.

3) Compile your standalone to an empty folder and put the previously moved .json file to that folder

I've set commands to force the presets to clear on open (shows the load is working fine inside max, just not in the standalone, but doesn't get me any closer!)
I've tried this inside an example patch, as well as my main patch. I'll paste my example below. (Using a json called testdata.json)
This has me completely stumped :). I'm hoping I've just forgotten something really straight forward, but who knows. I feel like I have tried everything three or four times during the last two days of working on this.

Many thanks for reading this far. B.