Layouts UI - Centering / Justifying Elements

Is there a way I can change the way the blocks within the Layout UI are displayed?

If I have a row that’s just a single 8-width column, currently, it aligns to the left but I wish for this to be central in the panel’s UI. The same in the popup window “select a layout” too.

You can try using a custom CSS stylesheet as described in the docs. Make sure to read through the excellent cookbook recipe that has practical examples of how you can target specific sections and areas of the panel in your css.