"All over Britain" or "from a wide area" is an unnecessary argument to win. To it's credit, the programme nailed it down as a hugely significant place (which was always obvious from it's size) and that's enough so far as the quarrying issue is concerned. Perhaps Stonehenge was only a sub-regional centre, but it's of "international" significance. It's all a matter of public perception.
Now, at least, they're proposing to damage a "hugely signifact site" so a big step forward has been taken.