I have recently completed an ornament catalogue for Thomas Gardner (fl.1735–65). On the day I submitted it for publication I found a book on eBay which has an ornament which is extremely similar to one he used: a pair of crossed conucopias with surrounding birds. In fact, it is similar to two he used.
Here are the two Gardner tailpieces, with the reference numbers I used in my article. (Click on the image to see a larger version of each.)
(T03; 32x56mm; used 1735–56)
(T04; 30x53mm; used 1754–56; note ribbons at lower centre replace two smaller birds)
And here is the mystery ornament (32x55mm; used 1785; note that it is signed "WP" at lower centre).
It is clear that the mystery ornament is not the exactly the same as either Gardner’s T03 or T04—though it is very, very similar to T03. The tailpiece appears to be a copy or, if the ornament was quite old when used by Saint, I guess both of Gardner’s ornaments could be copies of the Saint ornament.
The book with the mystery ornament in it is particularly interesting for being an unrecorded "Eighth" edition of Croxall's Fables of Æsop and Others … Illustrated with Cuts, issued in Newcastle by T. Saint in 1785.
Since Saint is very well known for issuing, in 1784, Thomas Bewick’s first major work, Select Fables. In Three Parts, it is possible that WP was another woodcut artists he employed. Not being very familiar with Saint’s (or Bewick’s) life I have no clue who this person might be.
If anyone has any suggestions about the identity of WP, or has seen this ornament in use elsewhere (I looked in many Saint publications without luck), or has seen other very similar ornaments, I’d be obliged for the lead!
[UPDATE: 27 Feb 2014. Here is another ornament, similar to T04 rather than T03, but it adds a further detail to the ribbons: a pomander bouquet (or floral pomander), which is hanging by a ribbon. It appears in an edition of Gulliver's Travels printed "for" Benjamin Motte (ESTC: t139027 [here]; Teerink 294 [here, on page 201]) in 1727 (making it earlier than the Gardner ornaments.]
[UPDATE: 2 July 2016: After my pictures disappeared again, I decided to give up on external hosts for large versions (1000px) of my images, and stick with the smaller ones (500px) that Blogger is prepared to host.]