Yoast Duplicate Meta Description

Hi everyone, would really appreciate some help with disabling my themes automatic completion of the meta description which is affecting the SERPs 🙁

I’m guessing it has something to do with this part of the header php – can anyone help? TIA

<title>
<?php
if ( is_single() ){ echo single_post_title().’ – Ventures’; }
elseif ( is_home()){ bloginfo(‘name’); echo ‘ – ‘; bloginfo(‘description’); get_page_number(); }
elseif ( is_page()){ single_post_title(); }
elseif ( is_search() ){ bloginfo(‘name’); echo ‘ | Search results for ‘.wp_specialchars($s); get_page_number(); }
elseif ( is_404() ){ bloginfo(‘name’); echo ‘ | Not Found’; }
else { bloginfo(‘name’); wp_title(‘|’);get_page_number(); }
?>
</title>