Affected the view of a world heritage site it seems, to be specific. I looked into it expecting it to be a bullshit reason, but apparently 22 million people visit annually. Perhaps it's a valid reason after all.
It was far enough that it would have been faintly visible from Bournemouth beach. I strongly doubt that a few dots on the horizon would have bothered any tourists.
This project wasn't killed because of the view. There were other financial (probably carbon based) interests involved.