Q: MBP Retina Display stuck on wrong resolution

I regularly connect my MBP to projectors and normally the laptop panel returns to it's normal resolution afterwards. Yesterday I connected it to a projector via HDMI and then when I was finished the retina display is now stuck on a lower resolution, as in default is 1440x900 and the max scaled is 1920x1200 and I usually have it on a higher resolution.

I've rebooted, reset the PRAM, tried to connect to projectors again, but nothing seems to want to let my MBP go back to allowing higher resolutions. Even a resolution switching app (QuickRes) won't switch up to higher than 1920x1200...

Any ideas? I need my screen real estate back!

Thanks