If a dash appears on the cover page of the brochure, it may be due to the Show as cover page area setting being set to display an area that has not been filled in the property's information (for the description supplement or housing information form). This could be, for example, a plot for sale that does not have a residential area.
You can correct this by either removing all areas from view, or by choosing to display the total area and/or the plot area, if any of these are available.