Here is a Coin set Booklet that is called Britain`s First decimal Coins . You have 5 coins the New 10p, 5p, 2p 1p and 1/2p coinsall are in high grade Extremely fine to Uncirculated condition . There are two guide cards in the booklet that explain what these coins will replace from the old money system and when these coins will be legal tender . They mention the D Day (Decimal Day)
The coins have the original lustre from when they were first minted and placed in the coin card holder
The 10p and the 5 pence coins are dated 1968
the 3 x copper coins are dated 1971 which were minted before being legal tender