I would try just duplicating the layout with the styles/theme that you want to use, then rename layout and make your needed changes to the new layout.
It's a two-step process; my guess is that you may be missing the second step.
The first step, which you've already done, is to save a set of custom attributes you've applied to a layout object as a custom "style" (or, alternatively, just save the changes to one of the built-in styles).
At this point, however, your new (or redefined) style is only available on the current layout. You'll note, in the Appearance tab, that the red arrowhead icon has now jumped from the "Style: " popup button (where, a moment ago, it was indicating local formatting not yet saved to a style) up to the "Theme: " popup button, indicating that locally defined or edited styles have not yet been saved to the overall theme itself.
The second step, therefore, is to click on the "Theme: " popup button and either save your new style(s) to the current theme, or save the whole enchillada as a new theme. That's when your new styles should become available file-wide, for every layout that uses that theme.
Did I read you correctly, and does this help?
Thanks for the replies on this.
I thought I had saved the theme with a new name, but in fact had only saved one of the styles.
Working through it again the theme title changed at the top and the new theme was available to all layouts.
I have also discovered the Manage Themes Item in the File Menu which opens a number of possibilities.
PO Box 1542 Armidale NSW 2350
Mobile Phone: 0429 428 700
Home Office Phone: (02) 6772 3933
COAMAS - Community Options, Advocacy, Management and Accounting Software