It does take a while to get the information up there, and it seems an age to a waiting author!
As for the ravine - the pics I have are of the uphill walk through the woods to the Castle. This is the safe (and very pleasant) bit, with the Ay burn (now called the Cor Burn) off to the right. Here the slope angles down and then drops the last forty feet straight down into the burn. If you look ahead, you'll maybe imagine the path turns uphill to the left, and the sunlight shows the open space where the ravine opens up in front of the castle.
The second pic shows the slope to my left, above me as I stand on the path taking the previous picture.
I don't think I have any pics of the the bit in front of the castle, but I'll check. Maybe this gives you a better idea - link
The guidebook says the land in front of the castle is less extensive than it was due to a landslip, and believe me it is is steep - I am not going to wander to the edge and peer over just in case....