Great Britain Scott #27 Information Needed

Came across this attached pair of GB#27 this weekend at an estate sale. This item appears to have been used upside down on cover based on the Glasgow, Scotland, double strike postmark. This pair also has 1 stamp with normal margins and 1 with a nice 'wing'. This item also has the bottom selvage attached that shows the inverted "POSTAGE".

So, what I am looking for, is to be pointed in the right direction concerning an online resource for GB#27. Am looking to find out info such as - What did the sheet look like? Is this stamp plateable? Which stamp in the sheet has the wrong watermark? Does the wide margin indicate this stamp was on the edge of the sheet? Etc.

Any help would be appreciated!! Thanks...Greg

Nice pair Greg

This stamp was printed in sheets of 240 subjects, arranged in 12 panes of 20 stamps, arranged in four horizontal rows of three. The stamps in each pane were in five horizontal rows of four. (Information from SG QV Specialised catalogue)

I am not aware if a plating study has been done for this stamp.

The watermark error occurs on stamp one of row 20.

The wing margin confirms that your pair is from the edge of one of the panes.

The 'POSTAGE' in the margin occurs between each pane. See the following image:

http://cdn.collectionsbase.org.uk/g...R051_08o.jpg

There may be further information in the book "The De La Rue history of British & foreign postage stamps, 1855-1901", available here:

https://babel.hathitrust.org/cgi/pt...w=1up&seq=13

Hope this helps!

Thank you so much, Bobby. Great info as usual. The picture helped a LOT and am already perusing the book.