Have a picture in front of me as I type, it's one on my photo collection, as my sight is missing the base.
The windage adjuster goes through a solid base plate that looks like it might mount to one of the smallbore rifles, there appears to be two vertical screws a the rear of this mount either side of a central hole, the main sight body can be folded back on this mount, just tried flicking back thru a few early books to see if I could spot it, but I'm juggling far to much at the moment, will look later, still have'nt found that original article.