I received a replacement GTX980ti from EVGA, quick turnaround which is great, thanks to EVGA.
But....after a few days, I got the exact same fault back again.
I don't want to just RMA the unit again without being sure that it's not going to happen again.  So far I've done the following:
 
Replaced the PSU.
Replaced the Motherboard.
Completely reinstalled Windows to take any chances of corrupt drivers out.
Ran memtest, which was fault free, then tried using each stick of RAM seperately to check for any issues.
Ran CPT stress tests to see if that's ok, all passed ok.
Had any other PCI items out of the motherboard incase of conflicts.
Using an old HD7970 out of my boys PC for now, which is faultless, similar wattage so would think that rules out PSU being iffy?
Put my 980ti in a friends pc to replace the 1060 that's he using.  It initially gave faults not wanting to see the card installed, but eventually installed.  He then had a few crashes included the sudden reboot when playing games that I was suffering from, although it was every time I started a game after a few seconds.  This and 2-3 BSOD's
 
I live within a few miles of the Penwortham depot, would I be able to visit or have a conversation with anyone there before I pull all my hair out?  I've not been able to play games properly for a couple of months now and I'm starting to get the shakes!!!
Please help me!
 
(PS, thanks in advance for anyone that can help)

UnstableOne
Maybe you haven't heard.  EVGA is not following through with warranties as well as they used to.  I wish it wasnt the case. 
I have suspicion that RMA dept is potentially causing damage to user products to refuse rma, or sending physically damaged products as replacements and then refusing warranty or support.
 
One suggestion I might give.  Use your phone or whatever to record videocard being faulty.  Then record your backup videocard functioning.  Youtube it or google drive and provide link.
Otherwise evga might try to blame you for issues to try to avoid honoring the warranty.
 
If you send or receive a replacement, take a thousand pictures or unboxing video for protection...

I'm not here to suggest that EVGA aren't doing there job correctly, I'm after help to sort out my PC.  So far they've been nothing but helpful with the RMA process.

RMA time. The problem followed the GPU to your friends system.
The other GPU (AMD) you had ran fine after you removed the 980Ti
You replaced everything else just about. I would RMA.

Hi
 
@UnkleEkO  What was the outcoming of te problem you had with your 980TI?   
 
@EVGATech_JoseC  What if you RMA a 980TI.. Do you get a refurbished of sparnkeling new 980ti?  

Glad we could help!

UnkleEkO
Hi RickDeerns, I'm pleased to report that they helped me out massively and swapped out my faulty 980ti with a brand new GTX1080.
All is still well with my system.

Game ON