Azda, you are correct it is a partially block die, there are also examples of 1843 penny DFF, both described in Bramahs, on the better grade examples the lower part of the E is still traceable and repairs to the E are evident on the later dates. I've also dealt with Ian, we do email now and again, but not sure why these would be called DFF when you can clearly see the trace of the E, so obviously not an F. Its not ike the inverted A for V on the halfpennies where its obvious a letter has been replaced I too refer to it as a DFF variety... Merely shorthand for a variety that is easier to use than DEF, Blocked lower leg of E, appears as an F.... Much like the descriptive ONF variety penny although we all know that it is truly an E with a partially filled die...