I got it, (finally), so kinetic isn't compatible with my version of Ubuntu. What you need to do is find an appropriate version from here:
http://wiki.ros.org/Distributions
In my case, I am running bionic, so i follow through on that page and eventually i get to install instructions for bionic which are:
apt install ros-melodic-desktop-full
So the key thing here is that ros-"crazy ros name"-desktop-full, where that crazy ros name has to be compatible with your debian / n00buntu version.
Now, it doesn't make it too clear in the instructions that you need to enable universe sources. Go into the /etc/apt/sources.list and uncomment out the universe repositories.
Then do an:
apt-get update
Kinetic should work for you at this point. I suspect this isn't working because you've got the lines:
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://gb.archive.ubuntu.com/ubuntu/ bionic universe
deb-src http://gb.archive.ubuntu.com/ubuntu/ bionic universe
deb http://gb.archive.ubuntu.com/ubuntu/ bionic-updates universe
deb-src http://gb.archive.ubuntu.com/ubuntu/ bionic-updates universe
Commented out. (Your lines will be different from these because you are using xenial instead of bionic). But either way these lines need to uncommented and you need to do an apt-get update after saving these changes.