This worked for me:

I wasnt able to change the scene directly so I just used a scheduler. Hopefully this will be of some use to others.

In CPP

cocos2d::ui::Button *button = ( cocos2d::ui::Button * )rootNode->getChildByTag( 8 );
    button->addTouchEventListener([&](Ref* sender, Widget::TouchEventType type){
        switch (type)
        {
                case ui::Widget::TouchEventType::BEGAN:
                        break;
                case ui::Widget::TouchEventType::ENDED:
                        //std::cout << "Button 1 clicked" << std::endl;
                        //Change Scene
                        this->schedule(schedule_selector(MainMenu::ChangeScene), 1.0f);
                        break;
                default:
                        break;
        }
});

    return true;
}
void MainMenu::ChangeScene(float dt) {
    // run main menu
    Scene *scene = HelloWorld::createScene( );
    
    Director::getInstance( )->replaceScene( TransitionSlideInR::create( 1.0, scene ) );
}

In Header

private:
    void ChangeScene(float dt);

You my good friend are amazing. We forgot all about putting it on there. We will update the Cocos API Guide tomorrow.

That is the way of doing it BTW.

Haha okay and thank you very much for the API Guide. I find it very helpful :D

Updated the button section on the API Guide accordingly.

Thank you very much for letting us know