Thanks Mike, was happy to sell you the 1843 DFF.
I have never seen a DFF on REG no colon, and very much doubt that it exists.
There is another 1843 REG colon die, which I think is just as worthy as the DFF as being recognised as a variety, and less common than the DFF.......it was probably just never seen by Bramah.
This is the repaired REG colon, which imo is the most obvious colon repair in the entire young head penny series, pictured below for information.