I will try to track down your discussions on the topic of Maundy v currency 3d. As a collector of both Maundy and 3d and 4d it is a topic dear to my heart. The reason I moved to focus on Maundy sets was precisely the difficulty in identifying true currency 1840s and 1850s 3d, especially for the key dates.
I had thought the irregular colons in the 1848 3d in the Portland collection may have distinguished it from the more regular colons I have seen in Maundy sets that year - but it seems you are less convinced.
At least 4d don’t suffer the same affliction.