On behalf of Katharina who sent in an email:-
I have seen this bird in June 2017 on my balcony. I live in London, just next to Hampstead Heath. We have green pattoys living in the park as well but I've never seen such a bird in my entire life and was wondering what it might have been since June.
The beak and it's feet were a very intense orange , I could not see its eyes but the area around the eyes was yellow or bright orange.
The weirdest thing was that the bird was very curious and not scared at all when I came and took a photo. I got a bit scared because I looked at it and it looked at me but I could not see any eyes on it. It stayed for another 10 min or so and then disappeared. All of its colours were really intense.