*Were* named differently. Modern coins just say "One Penny", "Two Pence" etc. That's all "silver" coins, because the old ones were withdrawn from circulation when the new, smaller ones were introduced; and most "copper" ones through natural wastage even though they are the same size as the original 1p and 2p coins.
Shame we didn't change to decimal coins years earlier - I have nothing but loathing for *any* measurement system which doesn't use base 10 (we have 10 fingers/thumbs and count in base 10), unless there is a very good scientific reason for using any other base (eg 2 and powers of 2 such as 16 for computers). There is a lot of sense in base 12 as a unit for packaging, since a 4x3 group of tin cans etc makes a squarer package than 5x2, but if we'd wanted to use base 12 it should have been universal for all measurement systems and we should have learned to count in base 12, with two extra single-character symbols to denote 10 and 11. Whatever we did should have been consistent; it is the lack of consistency which is the non-metric system's fatal flaw. Sorry, rant over :-)