Sorry to be a party pooper, Giok, but BOTH spellings are correct - there are two locations, one Irish (The Aran Islands are located at the mouth of Galway on the west coast of Ireland) and one Scottish (the Isle of Arran which is the largest island in the Firth Of Clyde) - the Irish one is spelt 'Aran', and the Scottish one is spelt 'Arran' - and both lent their names to uncannily similar woollen jumpers.

Shame on you as a Scot!!

;o)

Admittedly, the tendency is to use the 'Aran' spelling - but not because 'Arran' is wrong!

Here!