Only show custom categories marker from a specific parent

Hi,
I wanting to only show category markers from a specific parent. My store categories (parent and child) are as follows:
Fuel Stations
– BP
– Shell
– etc
Loyalty
– ebucks
– vitality
– etc
For example if a store has a category of Shell AND ebucks, then only get the marker from the Fuel Stations parent (ID of 12).

So far I am using this but not having any succes.

function mytank_custom_store_category_image( $store_meta, $store_id ) {

    if ( function_exists( 'z_taxonomy_image_url' ) ) {
        $terms = wp_get_post_terms( $store_id, 'wpsl_store_category' );

        if ( $terms ) {
            if ( !is_wp_error( $terms ) ) {
                if ( isset( $_GET['filter'] ) && $_GET['filter'] ) {
                    $filter_ids = explode( ',', $_GET['filter'] );

                    foreach ( $terms as $term ) {
                        //only return terms whose parent is Fuel Stations (ID)
                        if ($term->parent == 12){ 

                            if ( in_array( $term->term_id, $filter_ids ) ) {
                                $cat_marker = z_taxonomy_image_url( $term->term_id );

                                if ( $cat_marker ) {
                                    $store_meta['categoryMarkerUrl'] = $cat_marker;
                                }
                            }
                        }
                    }
                } else {
                    $store_meta['categoryMarkerUrl'] = z_taxonomy_image_url( $terms[0]->term_id );
                }
            }
        }
    }

    return $store_meta;
}