"This spiral staircase has been the main access to the upper floors since the 17th Century"
The spiral staircase from the main entrance on the ground floor to the first floor Great Hall entrance comprises of 14 stone steps in a clockwise direction. It was constructed in the 18th century around 100 years after the new extention was built and are the original steps which are cleverly arranged for right handed people.
The reason it is built to the right is for defence reasons. For example if you are right handed you would hold your sword in your right hand so when you climb the stairs you cannot swing your sword unless you were left handed as that is the side that is widest, however if you stand at the top of the stairs and were right handed you could easily defend your domain as your right handed sword movement would give you much freedom and could kill or easily disable your agressor as they climb the stairs.
The stairs from the bottom to near the top are pretty worn away so you can imagine all the foot traffic that will have climbed the stairs over the years, be that the ancient Hunter family, guards, guests and also the kitchen staff transporting the food up from the kitchen to the great hall.
There are several trip steps too, this is a special feature where each stone step is a different height and angle to unbalance attackers storming the castle.
Within this entrance there are several windows but these are all new additions added in the 19th century. There is a small round window on the North facing wall and this is the only original feature. The window immediately inside the door would have been the original entrance door.
Although the stairs are old they replaced a wooden spiral staircase or ladder accessing the Great Hall as the entrance door was located in a different position as to what it is today