I need to fit a safety gate to a steep stairway leading up to an unused attic room in my aunt's house. She is now wandering about the house and often goes up to the attic for no reason and I'm afraid she'll fall. I've looked at a few extending safety gates, which look like the sort of thing I had in mind, but none of them seem properly lockable (with a padlock or key). Can anyone recommend a suitable gate? This is quite a narrow stairway, so the fixed gate type probably won't be suitable as they are usually designed to fit a normal stairway.