After lots of searching I finally got round the problem of BP/WP not taking you to the registration page by adding the following file into wp-content/plugins/
bp-custom.php
<?php
/**
* Disables BuddyPress’ registration process and fallsback to WordPress’ one.
*/
function my_disable_bp_registration() {
remove_action( ‘bp_init’, ‘bp_core_wpsignup_redirect’ );
remove_action( ‘bp_screens’, ‘bp_core_screen_signup’ );
}
add_action( ‘bp_loaded’, ‘my_disable_bp_registration’ );