Season 12.5
By the time filming for the The Ark In Space rolled around, a large gray section had been removed from the right side of the Scarf. Other than that, this Scarf was identical to the Season Thirteen.
It is seen in several wonderful publicity photos from this time.
It is also seen in Genesis of the Daleks and Revenge of the Cybermen.
In Genesis of the Daleks, a large hole is seen in the large purple section on the bottom left.
Depending on your degree of obsession, the hole may be added or ignored. 
These are my choices for yarns for this scarf.
They are listed according to my personal preference in closeness of color match and weight to the original.
Feel free to go to my ‘Color Matching’ page, get the color chips and find your own yarns.
These patterns are subject to change as I find out more about the scarves and as yarn availability and colors change.
Season 12.5 in Brown Sheep Nature Spun Worsted
Season 12.5 in Brown Sheep Nature Spun Sport
Season 12.5 in Cascade 220 (worsted weight)