Finding information on the Arran connection is very hard, if anyone has any other information on this please get in touch.
In 1487 John Hunter of Hunterston inherited land at Lamlash (probably including Holy Isle) from Archibald Hunter who was his father (or his elder brother). In 1488 JH was (hereditary) Forester in Arran & Cumbrae with the perquisite of thirty shillings as the rent of one marcate of land at Lamlash. JH died at Flodden in 1513 and his son Robert Lord Hunterston obtained the Holy Isle in 1517, but sold Holy Isle to James Hamilton Earl of Arran in 1527.
Robert Hunter of Hunterston, a grandson of RLH obtained a tenancy of Holy Isle in 1551. (He was the son of Mungo Hunter, who died in 1547.) He was granted the tenancy by James Hamilton, Earl of Arran (who succeeded his father in 1529).
The duties of the forester were linked to the upkeep of open woodland which was suited to wild animals including deer which could be hunted by the nobility. Arran did not come into the possession of the Hamilton nobility until 1503. In 1488 Hugh Lord Montgomery was in charge of Arran