Many thanks Richard, thought you would have one!!
I have taken your picture, rotated it, and positioned same as my top 1844 DFF above. These two coins are now shown below.
It is difficult to compare those border gap features with the pixels available on the 1843.
It does seem to me, however, that the die flaw can just about be seen on your coin in the same position......... also the small protrusion above the F.
First impressions, therefore, are that this points to a single reverse DFF die used on both the 1843's and the 1844's.
If you reduced the size of your picture to get it within the forum 500Kb limit then please could you email me the original thanks?
If you can get same picture with more pixels so that border teeth can be seen more clearly that would also be great.