Dell XPS 13 9350 - booting into Windows but black screen

Since I purchased this laptop under two years ago I've had so many problems with it I've lost count.  It regularly gets bricked after Windows forced updates, most recently a few days ago.  I tried reinstalling Windows and managed it a couple of times but after a while the screen just goes black. The most recent time, the screen went black during re-installation so I now can't even finish the installation (and you can't do this in Safe Mode).  I know Windows is still trying to install as I can hear Cortana trying to set up.  But now I can't see anything in order to finish the installation so I'm stuck, unable to do anything.  I have no external monitor I can use but in any case, if this is a hardware issue, this is not a fix.

I've run diagnostics via F12 a few times and it shows no hardware issues but who knows, it could be.  Since I bought this, Dell have replaced almost all the hardware inc. motherboard and SSD. I'm not sure what else but I noticed today in BIOS in the log dated May 2016 (one of the times it was 'repaired') that it states, "...primary battery is not identifiable...". 

Before the black screen issue there were wifi problems too, none of the available network-related drivers worked.  

I am well out of my warranty now and close to buying a Mac but if anyone knows the cause of this black screen and can help, please let me know!  When this laptop works, it's amazing but I would say it's been in an unusable state for at least 3 months out of the 2 years I've had it which is totally unacceptable given how expensive it was.  

Dell support want me to keep paying to get this fixed even though clearly this laptop was faulty right out of the factory.  

If this could be a graphics card issue I have the tools to open the laptop and am happy to do the replacement myself (and wireless card replacement), I'd need a link to the right part though.

Any help on this would be gratefully received!

Thanks!