rdr2 stopped opening in full screen

[Beed64]

HELP
Hi all, I have a LG32GK650FZ 2560x1440 monitor. All 'was' fine,when the game loaded it was full screen in 1440. I unplugged everything to move it and now when it loads it is 3/4 of the screen. If I change the settings in windows to 1080 it's full screen. How do I get back my lovely 1440 graphics on full screen, and why would it alter just by unplugging and yes it was all switched off

 

[Beed64]

Tried that, didn't help but cheers for the idea. Just went into the game graphic settings and noticed that the resolution is set at 1920x1080, and is greyed out so I can't change it. I did think the graphics looked poor but I put it down to the little 3/4 screen size.