Hi and thanks so much for writing back!
I am making sure the lock is a moveable object (at least I think I am - using the root component)
The two objects are both blueprints, but that seems to be the problem. I have only attached blueprints before using Child Actors.
Here’s a Drive link with some screenshots and a video in case that helps.
https://drive.google.com/drive/folders/12l0zDvqpJ2r0u6_RBBsPlfOLVzaXwQN3?usp=drive_link