Only getting an A3 sized print...If I click portrait I get one end and landscape the other (maybe I should make a triptych now)
Not sure what I'm doing wrong
I've set a Custom Paper Size
this is usually caused by transposing the width and height settings in the custom paper dialog box. The entries are based on the sheet of paper, not the image itself. If the numbers are based on the size of a horizontal image, then things can get pretty weird, most common symptom is only a portion of the image is printer. I see this all the time where someone is printing a pano and enter the width of the pano into the custom box instead of the width of the paper.
So set the width based on the paper width, and the height based on the length of the paper. Then set the orientation dialog box accordingly. If you do it wrong then set the orientation box “wrong” it sometimes works. But if you enter things correctly it will always work.