Austen family portrait discovered?

Can you solve the mystery behind this illustration (left)? There's a possibility it may be a long-lost portrait of the Austen family in the 1780s. You can read the story so far here on Jane Odiwe's blog.  This picture has seemingly disappeared long ago, so if you know of its whereabouts, or have seen it in a sales catalogue, please contact Jane Odiwe via her blog, as she would love to hear from you.
Image supplied courtesy of Jane Odiwe.