Thank you Bob, you were absolutely correct. At the time, I couldn't submit the app for review, but after a few hours it was possible. So the issue was resolved eventually.A little patience goes a long way...

I was in the process of creating new certificates and updating the app in iTunes Connect.Everything went well, up until when I was submitting the new build via “Application Loader 3.0”. A window appeared stating: The resulting API analysis file is too large. We were unable to validate your API usage...