The denomination of the coin would be a big help and the nature of the mis-strike.
George III
King George was the British king.
Nobody "ruled" England in 1827. At that time England was part of the United Kingdom of Great Britain and Ireland. The King of the United Kingdom in 1827 was George IV.
He was British
who was the british monarch at the time of the american revolution
In 1827, the Prime Minister of the United Kingdom (which includes England) was Robert Jenkinson until April 10th, when he was replaced by George Canning. The Monarch at the time was King George IV.
British Parliament and King George III
The 1827 British Halfpenny is made from copper, weighs 9.337 grams and is 28 mm in diameter. There were 5,376,000 minted. They have a left facing King George IV (laureate Head) on the obverse and the seated figure of a helmeted and robed, shield and trident carrying Britannia on the reverse. The date is in the exergue below Britannia.
Nothing, King George III was the British Monarch.
King George III
King George the 3rd
King George V was King from 1910 to 1936.