Dockwra / Murray Covers 1680 - 1699

I am doing some research on Dockwra / Murray covers and was curious if any collectors had an idea on how many original Dockwra / Murray covers are in private hands from 1680 - 1682? The last known information I have is from the Sotheby's auction in 2011 stating 2 Murray covers and 4 Dockwra covers in private hands.

Additionally, how many of the early government Dockwra covers from 1683 - 1699 exist today?

Thank you!

In this article (2014) there is mention of at least 13...Page 5
Dockwra pioneered distinctive markings on all mail, and
although his service was extensive, there are only thirteen
known Dockwra covers or pieces extant today.…Seven of
these known pieces are in the British Museum…and one
that has been recorded but its whereabouts is not known
at present. There is also one small piece

https://www.stampnewsonline.net/Sta..._Dockwra.pdf

Thank you Perf12. That corroborates the Sotheby's listing commentary suggesting 6 in private hands of the original Murray / Dockwra covers.

I wonder how many of the government Dockwras exist from 1683 - 1699. It seems like the document you sent suggested any Dockwras from the 17th century were rare.

There was one in a GB lot.Corinphila auction 196. 2015
https://corinphila.ch/en/_auctions/...&lotno=1859#
Pic no. 9

Thanks Perf12. I went through a few different auction houses and come away with a tally of around 11 covers. I am probably missing a few so likely 15 or so covers exist with the government Dockwra.

Feldman 2, Stanley Gibbons 2, Spink 2, Cavendish 2, Harmers 1, Siegel 1, and Corinphila 1