For me the source is the Moorings BVI e-guide that you get after signing up for a charter (or at
https://www.moorings.com/download-the-british-virgin-islands-eguide). One pages 26-27 there is a "Red Zones Map" with the wording I gave in my previous post.
Strangely on page 48 of the same document it is said that Anegada is "Well worth the 11-mile sail from the North Sound,......"
We have contacted Moorings by e-mail for clarification.
.
