Thanks for that link sd4f, I'd also come across it hunting around for info. The D at right of crossed swords representing the next block of years makes sense, the only bit I felt sure about was 3 being the inspectors mark.
Even with my rifles build date of 99 an 03 proof seems late for a factory rifle, I spose I was assuming a 2000 proof because it made sense but I'm sure your right (alphabeticaly) with F being an 03. Perhaps a rebarrel, or maybe it knocked around a while before being sold off as PH went through it's death throws.