Have you read the book 'The Keys to the Temple' David Furlong. I have been thinking about your statement re Old Sarum being 6 miles from Stonehenge.
David Furlong states p.19 'Sir Norman Lockyer had found in the triangle of Stonehenge, Old Sarum and Grovely castle' That same distance 6 miles. Where is Grovely castle I cant find it on google earth and what shape triangle may this be.
As to your mistake join the club.