My BIOS version is F8, BIOS Date 19/09/2015. BIOS ID 8A06AGOU.
Just been to Gigabyte downloads website and noted that I do already have the latest BIOS. (F8). Thank goodness for that at least.
As I mentioned earlier, I did manage to get the GPU going for a short while when I had all of the parts connected outside of the case during the build so I took advantage and updated the graphics Drivers direct from AMD. Everything worked for a few hours even after many restarts. When I was satisfied all was working well, I placed everything back in the case, switched on and blank screen again. Only this time, no matter what I do or try, I just can't get anything from the graphics card when booting up, just a blank screen even though I'm sure Windows 10 has loaded waiting for my commands.
I have cleared CMOS and taken out battery already beforehand but it made no difference.