One of the reasons I chose this castle as the setting is because the original structure no longer exists and there is no documented history on the castle. We only have archaeological data to determine what we think it might have looked like and how it might have been designed, which leaves me lots of room for my over-active imagination.
Based on the layout features of what is believed to have been Brough Castle, it resembles the layout and size of Castle of Old Wick and was most likely built in the early 14th century. Andrew Spratt used this information to reconstruct a couple of drawings of what he believes may have been a likeness to Brough Castle.
These drawings were very helpful to me, as I created the fictional world of Braigh Castle and the characters that will appear in Highland Sanctuary. If you'd like to see these drawings, go here. Also, at this link are photos of the Brough Castle site from the air and more detailed information written by Robert Wilson Richmond, go here for the air photos.