How can I get Hyper V to detect my Ubuntu VM's IP Address

Ok, I figured this one out.

The tl;dr version:

sudo apt-get install "linux-cloud-tools-$(uname -r)"

Normally you'd install linux-cloud-tools-virtual to get the KVP daemon installed. Unfortunately, the kernel version that ships with Ubuntu 14.04.3 is 3.19.0-25-generic, whereas linux-cloud-tools-virtual installs the cloud tools for 3.13.0-65-generic. So obviously you need to install the cloud tools for your kernel's release version. To do that automatically you need to get your relase version using uname -r, as above.

Hope that helps somebody somewhere along the line.

seems like for 18.10 the sudo apt install linux-cloud-tools-virtual is what is needed again