Theme Update Issue

Hi,
I’m using a child theme but when updating the parent theme from 1.5.3 to 2.0.3 it causes some CSS issues.

You can see the site running theme version 2.0.3 here:
https://tinyurl.com/zyw5m2j

You can see the site using theme version 1.5.3 here, this is how it should look:
https://tinyurl.com/zrbhp9o

It seems to be affecting the container width, navigation bar, search field, home & interiors category. On internal pages its affecting the breadcrumb and page titles.
It’s also affecting the background colour of the menu in mobile/tablet view.

I’ve pasted my child themes functions file for your consideration:

<?php

/* Re-arranges order of sidebar and content, so product categories display first in mobile/tablet view. */

remove_action( 'storefront_sidebar', 'storefront_get_sidebar', 10 );
add_action( 'storefront_content_top', 'storefront_get_sidebar' );

/**
 * Alters the output of the homepage product categories on the Storefront theme
 * Affects the storefront_product_categories_args filter in /inc/structure/template-tags.php
 */

function sd_display_all_home_product_categories( $args ) {

	// Sets the maximum product categories to 50, you can increase this to display more if need be.
	$args['limit'] = 6;

	// Output
	return $args;

}
add_filter( 'storefront_product_categories_args', 'sd_display_all_home_product_categories' );

if ( ! function_exists( 'storefront_product_categories' ) ) {
	/**
	 * Display Product Categories
	 * Hooked into the <code>homepage</code> action in the homepage template
	 * @since  1.0.0
	 * @return void
	 */
	function storefront_product_categories( $args ) {

		if ( is_woocommerce_activated() ) {

			$args = apply_filters( 'storefront_product_categories_args', array(
				'limit' 			=> 3,
				'columns' 			=> 3,
				'child_categories' 	=> 0,
				'orderby' 			=> 'name',
				'title'				=> __( 'Product Categories', 'storefront' ),
				) );

			echo '<section class="storefront-product-section storefront-product-categories">';

				do_action( 'storefront_homepage_before_product_categories' );

				echo '<h2 class="section-title">' . wp_kses_post( $args['title'] ) . '</h2>';

				do_action( 'storefront_homepage_after_product_categories_title' );

				echo storefront_do_shortcode( 'product_categories',
					array(
						'number' 	=> intval( $args['limit'] ),
						'columns'	=> intval( $args['columns'] ),
						'orderby'	=> esc_attr( $args['orderby'] ),
						'parent'	=> esc_attr( $args['child_categories'] ),
						) );

				do_action( 'storefront_homepage_after_product_categories' );

			echo '</section>';

			echo '<ul class="products">
					<li class="product-category product home-interiors">
						<a href="https://preview.rosesandribbons.gridhosted.co.uk/product-category/home-interiors/">
						<img src="https://preview.rosesandribbons.gridhosted.co.uk/wp-content/uploads/2016/05/HOME-INTERIORS.jpg"></img>
						<h3>HOME & INTERIORS</h3>
						</a>

					</li>

			</ul>';	

		}
	}
}

/**
 * Add logo without Jetpack
 */

add_action( 'init', 'storefront_custom_logo' );
function storefront_custom_logo() {
remove_action( 'storefront_header', 'storefront_site_branding', 20 );
add_action( 'storefront_header', 'storefront_display_custom_logo', 20 );
}

function storefront_display_custom_logo() {
?>
<a href="<?php echo esc_url( home_url( '/' ) ); ?>" class="site-logo-link" rel="home">
<img src="<?php echo get_stylesheet_directory_uri(); ?>/images/logo.jpg" alt="<?php echo get_bloginfo( 'name' ); ?>" />
</a>
<?php
}

/**
 * Re-arranges order of Cart section in header
 */

add_action( 'init', 'jk_remove_storefront_cart' );
function jk_remove_storefront_cart() {
add_action( 'storefront_header', 'storefront_header_cart', 35 );
remove_action( 'storefront_header', 'storefront_header_cart', 60 );
}

/* Removing sections from homepage */

function rosesribbons_remove_recent_products_homepage() {
	remove_action( 'homepage', 'storefront_recent_products', 30 );
}
add_action ('init', 'rosesribbons_remove_recent_products_homepage');

function rosesribbons_remove_popular_products_homepage() {
	remove_action( 'homepage', 'storefront_popular_products', 50 );
}
add_action ('init', 'rosesribbons_remove_popular_products_homepage');

function rosesribbons_remove_onsale_products_homepage() {
	remove_action( 'homepage', 'storefront_on_sale_products', 60 );
}
add_action ('init', 'rosesribbons_remove_onsale_products_homepage');

function remove_loop_button(){
remove_action( 'woocommerce_after_shop_loop_item', 'woocommerce_template_loop_add_to_cart', 10 );
}
add_action('init','remove_loop_button');

/* Alters copyright info */

if ( ! function_exists( 'storefront_credit' ) ) {
    function storefront_credit() {
      ?>
	<div class="site-info">
	<img style="margin-bottom: 10px;" src="/wp-content/uploads/2016/06/payment-logos-2.png"></img>

		? <?php echo get_the_date( 'Y' ) . ' ' . get_bloginfo( 'name' ) ; ?> - Flowers - Gifts - Interiors | All Right Reserved  <span class="listed-web">Listed Website Design T: 01698 40 20 30</span>
 	</div><!-- .site-info -->
	<?php
    }
}

/* Removes long description field from post editor */

function remove_product_editor() {
  remove_post_type_support( 'product', 'editor' );
}
add_action( 'init', 'remove_product_editor' );

Any help much appreciated.