thanks for the response, looks like its back to my old windows machine for the time being
This is what Adobe Chief Customer Advocate Jeffrey Tranberry said yesterday in the official Adobe feedback forum:
The current Nikon Tethering SDK uses an API that was deprecated by Apple in El Capitan. Nikon needs to update their SDK to use a different API. Once they update their SDK, we can test and integrate it in a future update.
If you add your vote and opinion to that topic, Lightroom: Can't use tethering with Nikon and Leica after installing MacOS 10.11 El Capitan, you'll be notified of any updates on the issue.
So I guess its either Nikon needs to fix their problem with Apple, or Apple needs to fix their problem with Nikon. Then Adobe can get their problem with Nikon and Apple rectified.
There are a couple of things we will not see happen.
a. The major camera manufacturers will not support Adobe DNG Format.
b. Adobe will not produce Digital Cameras.
c. Adobe will not produce Computers.
d. We will never be able to expect Adobe to be fully accountable for our workflow in the processing of our digital image capturers.