I found this Q&A that I though would answer my question https://learn.objectiflune.com/discourse/t/planetpress-connect-designer-imposition-flawed/1740/1 however something isn’t working for me.
I had a similar issue so I copied the print section properties in that example. In the Output Preset if I use the same settings as are in the screen shot I get the message “The impositioned pages will not fit on the selected media size” and no preview. If I change “Auto-Position” to “Scale to Fit” the preview is available but shows the impositioned pages in portrait.
Where should I be looking to resolve this?