HELP! Custom Resolution no longer showing in game after update to RTX 3070

[TheMindBuddah]

Hi Guys and Gals!

I have often googled for solutions and its often brought me here and this is the first time i have not been able to find a solution online. So am hoping you guys can point me in the right direction!

Have recently upgraded my 1070 to a 3070 and can no longer run Elite Dangerous in 7680 x 1440 in a window, across my 3 screens. Really can not figure out what's wrong? Really hope somebody can help, or at least point me in the direction of a solution!

Full description.

Have been running Elite Dangerous in windowed 7680 x 1440 across 3 screens for about 8 months with no issues. (See Video). The way I do this is to run a custom resolution of 1440 on two 1080p side monitors (Iiyama 27" G-Master Black Hawks). Then add a custom resolution to my centre monitor (ASUS ROG SWIFT PG278QR) of 7680 x1440. Then simply select in game 7680 x 1440 in windowed mode. All Monitors are on DisplayPort. Its the only game I use the triples for as everything else is played single screen.

Nvidia Surround is not an option as even with CRU my centre monitor don't play nice, often resetting to lower resolutions or borders after restart

Since installing the 3070 with completely fresh driver install. I can still set the custom resolutions, but while if I move the ED to a side monitor it recognises the custom 1440 in game. On the centre monitor there is no option for the 7680x1440 as like before.

Things I have tried

Have rolled back to earliest RTX driver.
Installed latest RTX driver.
Reinstalled windows 10.
Tried to see if it was just ED, but its all games.
Have put the resolution in the graphics xml of ED and it displays across all screens for a second, then resets to 2560x1440 single screen.

Please, has anybody a solution or experienced this?

Really at my wits end and lost a whole weekend trying to sort it!

Is this Nivida or Windows?