Colin, it would fit if you'd bought it, it seems to fit more between size 38 and 40 than 42 as tagged on it.
This pattern has quite wide shoulders independently of its size, but all the other measurements are close to size 38 or to slim fitted size 40.
I have a 39" chest so it probably would be good there. Believe me when I say I really thought about it and came back to the FS thread many times to have a look. The 19" shoulder width threw me off so I played it safe.