How can I turn off alternative layouts in the pages panel?

Hi,

For some reason my pages panel as split into two columns, header A4 V and A4 V 2, I assume this are alternate layouts for HTML export or something.

How can I turn these options off? I don't need this functionality right now and I've got pages in one column that I need in the other. Don't seem to be able to find the controls for this.

Thanks