[karlbenn73]

I want the Register link on the forum page to redirect to my websites Login / Register page http://lunchdone.co.za/my-account/ and not use the WP login form.

How can I solve this challenge?

[Robin W]

suspect this is what you are after – add it to your functions page in your child theme

add_filter( 'register_url', 'my_register_page' );
function my_register_page( $register_url ) {
    return home_url( '/register/' );
}

https://codex.bbpress.org/functions-files-and-child-themes-explained/