Need Help To Modify Code That Adds RRP to Woo Commerce

Hi, I need to add a RRP to Woo Commerce I have the code for it here courtesy of business bloomer:

/**
* @snippet Display RRP/MSRP @ WooCommerce Single Product Page
* @how-to Watch tutorial @ https://businessbloomer.com/?p=19055
* @sourcecode https://businessbloomer.com/?p=20727
* author Rodolfo Melogli
* @testedwith WooCommerce 2.6.4
*/

// -----------------------------------------
// 1. Add RRP field input @ product edit page

add_action( 'woocommerce_product_options_pricing', 'bbloomer_add_RRP_to_products' );

function bbloomer_add_RRP_to_products() {
woocommerce_wp_text_input( array(
'id' => 'rrp',
'class' => 'short wc_input_price',
'label' => __( 'RRP', 'woocommerce' ) . ' (' . get_woocommerce_currency_symbol() . ')'
)
);
}

// -----------------------------------------
// 2. Save RRP field via custom field

add_action( 'save_post', 'bbloomer_save_RRP' );

function bbloomer_save_RRP( $product_id ) {
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
return;
if ( isset( $_POST['rrp'] ) ) {
if ( is_numeric( $_POST['rrp'] ) )
update_post_meta( $product_id, 'rrp', $_POST['rrp'] );
} else delete_post_meta( $product_id, 'rrp' );
}

// -----------------------------------------
// 3. Display RRP field @ single product page

add_action( 'woocommerce_single_product_summary', 'bbloomer_display_RRP', 9 );

function bbloomer_display_RRP() {
global $product;

if ( $product->product_type <> 'variable' && $rrp = get_post_meta( $product->id, 'rrp', true ) ) {
echo '<div class="woocommerce_rrp">';
_e( 'RRP: ', 'woocommerce' );
echo '<span>' . woocommerce_price( $rrp ) . '</span>';
echo '</div>';
}
}

However I have a pretty complex currency converter added to the website and if for example I add £10 to the RRP when the converter is used it changes it to $10 which is obviously wrong is there any way to just add a static £ symbol so that every RRP remains in pounds regardless of the currency change. Thanks!