You cannot easily do that. The Bookmark+ layout generally follows that of vanilla Emacs, but more information is provided in the "heading" (first few lines).
This "heading" information includes the bookmark file and the current filtering type (kinds of bookmarks that are shown). That is why more than one line is used. The bookmark file location alone can be wide, so it is placed on a line by itself.
There is no need for column headings, as it is pretty obvious that one is the bookmark name and the other is its location (e.g., file). And as there is no need for column headings, there is no need for an Emacs header line (which scrolls with the window, so that it is always visible, to let you know which column is which). The header line you show is pretty useless, IMHO, but even if you like it, you would need to do some programming to modify Bookmark+ to use it.
(As for the columns you show, I assume that you know that you can toggle showing the file column, using
As for your two-character indentation: Bookmark+ uses the first 4 characters of each line for markers:
- First char:
) for deletion flag or ordinary mark (or unmarked).
- Second char:
t if the bookmark has tags (or
if it has none).
- Third char:
) for temporary bookmark or annotated bookmark (or neither).
- Fourth char:
* if the bookmark has unsaved modifications (or
So bookmark names are always "indented" 4 chars.