I have tried to upload a test image to my CloneDeploy server which is a VM running Server 2016 r2.
The image I am uploading is Win 7 HP that is a VM that has been configured and sysprep'd and set to the OOBE.

I have turned on the Win 7 VM and let it boot up until prompted to start the setup. I have then gone to Tasks -> Start Computer Task selected my Image -> upload. The image has the MAC address of the Win 7 VM and it appears to start without error.

The problem I have is that after starting nothing happens. I've left the upload run for roughly 24 hours and in All Active Tasks it shows a status of '0' and nothing else.

I believe you are missing a step. Are you following the getting started documentation?

You need to boot into an imaging environment to upload and deploy images. It can be pxe or iso/usb.