Mail header size - any way to shrink height?

Hi all, I have a little issue with the display of my mails in both the preview pane and when I open the mail in a full screen view. The header seems to be taking up an inordinate amount of real estate and I wonder if there is any way to make it less high?

My OS is Win11 and my screen is a 24" screen with a native resolution of 1920x1080 but I have the scale set to 125% as I need this to be able to see the rest of “life” without using the old ctrl and mouse wheel to zoom things.

This is what I see now and you can see that the header takes up over 1/4 of the real estate:
Cheers, Paul