Trolls are notoriously nasty and this one has taken up residence in a beautiful spot overlooking a park. He's not stupid, his cave is out of reach of muggles, but not brave geocachers. You'll need to be careful and scramble a bit (No one said it was easy adventurer).
The surrounding park is very busy and usually always full of muggles at the weekend. An early morning/evening approach will usually find the troll sleeping. Good luck brave adventurer! Be careful as it can be slippery when wet! If caching with little ones, safety first!