RichG

d stands for dineri, as in the Roman coinage.

I'm not sure if you meant the old 1 and 2p coins survived. They didn't. They were completely new for decimalisation and didn't run parallel with any old coinage.

The coins survived decimalisation

Only the:
6p (2 1/2 new pence)
shilling (5 p)
florin (2 shillings) (10 p)
survived

The coins that passed on included:

old penny
(a big copper coin, bigger than the 2 new pence and 50 new pence coins (the 50 new pence coin has shrunk with a new one coming out in 1997-98))

3 pence
(about the size of a new pound coin and the same colour too)

Crown (big coin which I think was worth 5 shillings or 25p)

Also possibly coins such as the farthing (1/8th of a penny?)

A new coin, the 1/2 new pence, was issued at decimalisation but has been withdrawn since)