[mothered]

Yes currently using a dual booted Linux OS from which I installed with the same method.

Then your method Is obviously not the Issue.

It's come to a trial and error scenario. I'm eager to see whether the other recommendations work.

I have gotten further.

I tried a smaller USB, this one is 8GB and I wrote the image again with DD.
This time when I boot from USB Partition 1 - It spits out some text but then reboots. I then tried booting from USB Partition 2 this leads to the screen filling up with text, then exiting to a blank black screen.

Next I will try editing the BOOT config file as suggested on the Qubes Troubleshooting guide.

For some reason, It may well be a USB Issue.

As stated In one of my previous posts, have you tried booting directly from disc?