Default DSpace frontpage shows two Search box, one in the homepage body and one in the menu.
To remove the one in homepage body, insert this into [dspace]/webapps/xmlui/themes/Mirage/lib/xsl/core/page-structure.xsl
<xsl:template name=
"disable_front-page-search"
match=
"dri:div[@id='aspect.discovery.SiteViewer.div.front-page-search']"
>
</xsl:template>
then refresh….