About the 10p:
The British decimal ten pence (10p) coin – often pronounced ten pee – has a value of ten one-hundredths of a pound sterling. Its obverse has featured the profile of Queen Elizabeth II since the coin's introduction in 1968, to replace the florin coin in preparation for decimalisation in 1971. Four different portraits of the Queen have been used on the coin; the latest design by Jody Clark was introduced in 2015. The second and current reverse, featuring a segment of the Royal Shield, was introduced in 2008.
 
Five pence and ten pence coins are legal tender only up to the sum of £5; this means that one can refuse payment of sums greater than this amount in 5p and 10p coins in order to settle a debt.
 
The ten pence coin was originally minted from cupro-nickel (75% Cu, 25% Ni), but since 2012 it has been minted in nickel-plated steel due to the increasing price of metal. From January 2013 the Royal Mint began a programme to gradually remove the previous cupro-nickel coins from circulation and replace them with the nickel-plated steel versions.
 
As of March 2014 there were an estimated 1,631 million 10p coins in circulation, with an estimated face value of £163.08 million. Credit: https://en.wikipedia.org/wiki/Ten_pence_(British_coin)