Can an AUv3 on iOS access the standalone plugin's sandbox folder when running under another host?

I’d like my AUv3 on iOS to be able to access sounds that I upload using iTunes to the Standalone plugin’s documents folder. Running the standalone, this works fine using:
File::getSpecialLocation (File::userDocumentsDirectory), which points to:

However under another host this points to somewhere in:

Is there a way the plugin can access the standalone’s sandbox or is there a betterway to access files?

Should have look harder. Discussion here: