To me,an English coin is one that was issued right up to & including the Pre-Union issue of 1707.Some people say that the first English coins were struck during the reign of King Egbert (802-39).Other people include the Anglo-Saxon coins.What is your definition of an English coin, apart from the fact that it is not Scots or Irish?
I would have to say any coin that was struck under the issuing authority of the English or British government - at any time in history.
I would say that an English coin is a coin issued under the authority of the King (or Queen) of England for the use of the Kingdom of England. A British coin is one issued under the authority of the King (or Queen) of the United Kingdom of Great Britain (and Ireland/Northern Ireland, when appropriate) for the use of the United Kingdom. I do understand that by my definition, coins of the Empire (as opposed to the Commonwealth) could be considered "British." I would argue that if such coins were minted for use in the colonies (even if they were minted in Great Britain), they were coins OF those colonies/dominions, rather than of Great Britain.
KLJ,it must be remembered that the Farthing fractional coins can be regarded as British coins,even though the 1/4 Farthing (1/16d.) & 1/2 Farthing (1/8d.) were used in Ceylon,& the 1/3 Farthing (1/12d.) was used in Malta.The silver 3-Halfpence (1-1/2d.) was used in the West Indies,but these are also regarded as British coins.