Which of the following two sentences sounds "more English":
Being 15 minutes in the icy water he turned blue.
After 15 minutes in the icy water he turned blue.
And if both of them sound "pretty English" do they differ in meaning or style?
The second one (after 15 minutes...he turned blue) is the more natural of the two. With the being version, you'd want to move "15 minutes" after "water", "Being in the icy water for 15 minutes". And you can eliminate being: "In the icy water for fifteen minutes, he turned blue."
You could also say:
In the icy water for fifteen minutes, he had turned blue by the time we got him out.
In your "after 15 minutes" version, you're describing the situation and the ensuing result. In this version, with the past perfect, we describe the result after-the-fact, as one fully realized as of the time we got him out.