There's a 2013 Vanquish with 7k miles going through Manheim auctions in Washington on 18th July, in case anyone is interested. Grade 1 condition (highest), 3 keepers, s/history awaited. Not sure how its found its way there, but it looks great in the pics!
As you say, unusual not to be the subject of a retail sale. Purely idle speculation, but wonder if it might be an executor sale, or perhaps a motor dealer in need of quick cash.
In due course, If you discover the gavel price Johnny, please tell us.
