SOLVED - the USB firmware on the projector needed updating - power of posting!

I have a Philips Picopix Max projector which I use for watching media and playing games with my son.

I used to use a HDMI cable to connect to my laptop, but it broke yesterday. I have a USB-C lead, though.

The USB-C connection is basically plug and play when I'm using my windows partition; select USB-C input on the projector and you get a nice HD display.
However, with KDE Neon the projector is only showing a small portion of what my laptop is displaying, zoomed in to a low resolution of 960 x 540. The projector should display up to 1920 x 1080.

In Neon's display settings, I can select all the normal resolutions for the laptop screen up to 1920 x 1080, but if I select the projector I can only choose from a small selection of possible resolutions, 960 x 540 being the highest. And, like I said, it doesn't display the whole screen at a low resolution, it zooms in to show part of what my laptop is showing, a portion of the screen I guess to be 960 wide by 540 tall.

Also, if I press fn-f1 and select 'unify outputs' the LAPTOP SCREEN becomes 960 x 540 to match the projector res, also zoomed in so I can't see the whole screen.

None of this happens using HDMI on Neon, but I'd like to use USB-C if I can; at the very least it means I don't have to buy another HDMI lead!

Again, I get full res using windows.

Any ideas / solutions, anybody? I'd be grateful for any advice.

Thanks.

https://www.dropbox.com/s/jcr2nk9bmgbvanf/Res.png?dl=0

https://www.dropbox.com/s/he5sdfifsqopdlf/IMG_20210208_104411172.jpg?dl=0