There are three variant mintings of the 1918 and 1919 British Penny. The pennies minted in London have no mintmark.
The mintmarks "H" for the Heaton Mint, Birmingham, or the "KN" for King's Norton Metal Company are to the left of the date on the reverse and are extremely small.
The 1919 British Penny has no mintmark if it was minted at the Royal Mint.
If it was minted at either Heaton or King's Norton, there will be a very small H or KN to the left of the year on the reverse of the coin.
Most British pennies will not have a mintmark because they were all minted at the same place - The Royal Mint.
During Queen Victoria's reign, coins were often minted at two or more different mints, and to a much lesser extent, some of the coins of George V. Most commonly it will be "H" for Heaton, Birmingham, or "KN" for King's Norton.
The mintmarks will be on the reverse at the bottom in the exergue below the date or to the right of the date.
British King George V Pennies were issued in most years from 1911 to 1936 inclusive. There were no Pennies minted in 1923, 1924 or 1925, and only 8 (it is thought) in 1933.
Those minted at the Royal Mint have no mintmark.
The following are the exceptions.
A small quantity of the overall mintage of the 1912, 1918 and 1919 Pennies were minted at the Heaton Mint in Birmingham and have a very small "H" to the left of the date.
A small quantity of the overall mintage of the 1918 and 1919 Pennies were minted at the King's Norton Metal Company and have a very small "KN" to the left of the date.
In exergue
The H mintmark letter is for Heaton, in Birmingham, England
On the reverse below Britannia is a dividing line, called an exergue,
in which is the date; the mintmark is to the left of the date in the corner.
--------------
H
1912
Like that.
The 1932 British Penny does not have a mintmark. They were all minted at the Royal Mint, London.
There is no mintmark. All 1898 British Pennies were minted at the Royal Mint.
The 1944 British Penny does not have a mintmark. They were all minted at the Royal Mint London.
King George V
Quite aside from the fact that all 1911 British and British Empire Pennies feature George V and have GEORGIVS V inscribed on the coin, if the head is facing towards the left then it is George V. If the head is facing to the right it is Edward VII.
1936 was the last year British coins were minted with the likeness of George V. The 1936 Penny is far from rare and you should have no trouble finding one.
Pre-decimal British Pennies were made from bronze from 1860 until 1967.
If the coin has no country name on it, it is British, otherwise, it could have come from any of the 50 plus British Empire/Commonwealth countries.
You are thinking of coins of George V. Only one nation has not demonetized George V coins: Canada. This is the only place in the world that a George V coin can legally circulate. However, the George V farthing is almost the same size as the British penny and can VERY RARELY be seen in circulation.
I am unfamiliar with the reference to "centre diamond" on an Australian George V Penny. Please provide more information.
A British 1912 bronze Penny (George V)(minted at Heaton - mintmark = H), uncirculated and in absolute mint condition could fetch up to £250 GBP. If it has been circulated but still in good condition, it might fetch anything from £10 to £90 GBP. A British 1919 bronze Penny (George V)(minted at Heaton - mintmark = H), uncirculated and in absolute mint condition could fetch up to £800 GBP. If it has been circulated but still in good condition, it might fetch anything from £15 to £250 GBP. The values quoted are the best possible for the best specimens in their grades, but may be significantly lower due to varying demand for the coin and the prevailing economic climate. A reputable coin dealer will be able to give a more accurate valuation based on inspection of the coin.
King George V
Yes. George V died in January 1936 but the coins had already been minted. The British West Africa Pennies that were issued and circulated had both George V on the earlier coins, and Edward VIII on the coin issued later.
It depends on the nation.
In 1919 the British Monarch was George V.