"I mean Buckingham Palace has never hired a professional public relations outfit let alone a Madison Avenue type and they would throw up their hands in horror at the very idea"

This quote by Anthony Holden is referring to the British Royal Family's technique to public relations. He is recommending that Buckingham Palace has never ever worked with a professional public relations company, nor have they ever considered employing a Madison Avenue type company. This implies that the Royal Family has a conventional method to public relations, and that they would be appalled at the idea of working with a professional company. This quote is also recommending that the Royal Family is not interested in modernizing their public relations technique, which they choose to manage it internal. This quote is a commentary on the Royal Family's method to public relations, and how they are resistant to updating their method.