Array sorting assistance

If you change the saved date format to YYYY-MM-DD HH:MM (always with leading zeroes). You can use the usort() array sorting function from php.

usort( $array, function( $a, $b ) {
    return strcomp( $a['show_date_and_time'], $b['show_date_and_time'] );
} );

Without changing the date format you need a more complex compare callback:

usort( $array, function( $a, $b ) {
    $date_a = date_create_from_format( 'j-m-Y H:i', $a['show_date_and_time'] );
    $date_b = date_create_from_format( 'j-m-Y H:i', $b['show_date_and_time'] );
    if ( $date_a > $date_b ) {
        return 1;
    } else if ( $date_a == $date_b ) {
        return 0;
    }
    return -1;
} );