There is only one Sweet Chestnut at Hunterston and that is located between the Mansion House and the Walled garden. The tree is on the side of the unmarked path that goes from the side entrance gate of the walled garden to the gated access near the tennis court at the Mansion House.
It is suggested that Sweet Chestnut Trees were planted by the Gentlemen of the House on country estates, (i.e the laird) as they were a beautiful sight and were usually placed near the favourite walk of the Gentleman so it could be admired each time he passed.
It is entirely credible this is the case at Hunterston as it is on a pathway that goes from the Main House to the Main Garden. The pathway is shown in black below with the tree brightly shown near the centre.