Yes, there are a ton of forts around here. The one here in Edinburgh at Crammond was huge, and had a port to allow supplies to be shipped in.
I also find the details of who was around quite interesting. The info boards also talked about the Nervians, and they also name their commander Flavius Betto due to some of the inscribed stone work left behind. Its amazing that we know his actual name after all these years. I'm hoping to see those carvings tomorrow, because there are in the museum here in Edinburgh !
You can read a little more about them in the extra pics I've uploaded below (pics of info boards at the site).