Hi Owain! Good luck with the debugging mate. Just as a reference, I'm sure you've seen this already? https://apidocs.umbraco.com/v9/ui/#/api/umbraco.services.editorService The first code example on the page takes you through opening a media picker. If you wanted to, you could add a bit of javascript before line 14:

debugger;

Then you can inspect the value returned by the submit function. That'll give you an idea of what the model you are working with is? You can inspect everything about your javascript at this point - not only what's available from this function but what's available in the outside scope. So you should be able to track down why

$scope.control.value

doesn't exist in your code. Hope this helps!