.. or alternatively applying an object style to all frames. Is there any way to do this with a few clicks rather than editing every single frame? If not then I probably have to try scripting.
In this case I need to change them all from "below current line" to inline style.
In a MIF file, you could try a global search/replace for <FrameType Below> to <FrameType Inline> within the context of the <AFrames ... > section.
And Rick Quatro has a Framescript that does this.
Thanks for the ideas. Concerning Rick Quatro's script I found several references leading to deleted Adobe pages, but nothing on his website. In case this is free to use, do you happen to have a (still working) link?