Well, don't be shy next time. For future reference I'm a 2XL owing to my broad shoulders. I think that's a Medium in The States.
Looking at your pics, I think that the New York Natural History Museum has done a much better job of the dinosaur display than the one in Kensington, London that I visited recently. I left feeling a bit disappointed.
You have a wonderful picture of the Stegasaurus which I think is my favourite dinosaur now.