ATS and its effects on loadURL and local HTML Files

I have an application that is affected by the new ATS protocol and the NSExceptionDomains key you can add to InfoAdditions has worked a treat along with changing to https where I can, but this has got me worried, I make use of the StageWebView to load local HTML files that have been generated from my application.

I use:

var lwf:File = File.cacheDirectory.resolvePath("generatedPageFolder/htmlFileHere.html")
swv.loadURL (lwf.nativePath)

This allows me to find the file that has been created and determine its full path and load it into the waiting stageWebView.

My question is how do I add the cacheDirectory to the list of exception domains so the file will still load, I have tried adding file:// to no success and I am struggling to think of another way to do this.

Many thanks.