Could you please try moving a few images from your iPhone to your desktop and then try Importing them?
The Lightroom DNG files on the iPhone 7+ are not seen in any way on the Mac. Photos does not see them, neither iTunes (as App files) and obviously not even Lightroom. Sp there is no way to drag them anywhere since they are not visible.
Apart from the DNG files you've shot on your iPhone do you have any other DNG files or can you downloading a few sample DNG files over the internet and then try to import them in Lightroom?
No since the camera app of the iPhone cannot shoot RAW and since Lightroom App has the ability shoot Dngs I am trying to avoid buying another App. I have done all I could yet re upload from iPhone to Lightroom CC via the internet yet yesterday when I was still at home nothing downloaded although in the mobile panel in Lightroom CC I see them as downloading - and I have only 12 images.
Now I'm in London and I wanted to test the iPhone 7+ cameras and I guess unfortunately I'll need to buy another App. I have only roaming internet on my phone and it will cost me a bomb to stay uploadimg and downloading all the DNG files!!!!