Bumping this older topic. I was very fortunate to pick up a few stamps in the dime box at the latest stamp bourse. I saw this group, and snatched them up. When I got home and was able to do some higher definition scans, the "Short extra flagstaff" variety appeared on not one, but two of them. These are Gold Coast, 6d and 1sh varieties, Scott 110, 111, and SG 115b, 116b.
First, 6d:


Then, the 1sh:


I find it interesting that my 6d version also has that dot mentioned by the OP. Maybe they have a short extra flagstaff version after all?
Anyway, a US $0.20 investment has a catalog value of 700 pounds in my 2010 SG catalog. It's a pity that the 1sh has some cut perfs on the lower left. But, I'm not complaining ...