Gouby has identified two doubled variations of the Bramah 10c (his 1848C) on his website. He names these as types Ca and Cb, and I believe Richard's doubled example is a Ca, same as the one in my collection, 2nd picture below.
There are many examples of fully doubled dates in the Victorian Copper Penny series. Whilst these are interesting to look at I prefer not to think of them as true varieties because, unlike the man made repair of the 8/7, the fully doubled date has occurred as part of the striking process. Both the non doubled 1848C and the double 1848Ca are, therefore, I believe from the same die pairing.
So, for example, on the 1848C, Ca and Cb I think you will find that they all have identical other legend features such as the picture of DEI which I also attach in an additional post immediately below so I can clearly show the protrusions .