Solved with adding actions to my functions.php, here is the code for anyone else’s reference coming up against this.
function ea_cooks_label_singular() {
return 'Cook';
}
add_action('tribe_organizer_label_singular','ea_cooks_label_singular');
function ea_cooks_label_plural() {
return 'Cooks';
}
add_action('tribe_organizer_label_plural','ea_cooks_label_plural');
I also needed an archive page, so:
function ea_add_cooks_archive( $post_type_args ) {
$post_type_args['has_archive'] = true;
return $post_type_args;
}
add_filter( 'tribe_events_register_organizer_type_args', 'ea_add_cooks_archive', 10, 1 );