The rifles sights illustrated were sold on the internet auction sight eBay in June 2016 for US$536.00.
MLAGB) for many years.
The following is extracted from An Announcement from Parker-Hale published in the MLAGB Newsletter No. 4, July 1988.
"The Parker-Hale .451 Volunteer Rifle is now offered in limited production, fitted with Dr. Goodwin’s Orthoptic sights. These authentic reproductions of Dr. Goodwin’s Orthoptic Sight illustrated on page 31 of the Manual of Rifling and Rifle Sights by Lord Bury in 1864 are accompanied by an interchangeable element front sight which follows the original design. The fitting of Dr. Goodwin’s Sights will add around £225 to the retail price of the rifle which will be available to special order through Parker-Hale Dealers."
How many such sight sets were made (and how many so complete survive today)?
Images reproduced courtesy: John Romans