Don't forget, they see differently than we do. Depth can be difficult for them sometimes. I have a foyer with a 2 story high ceiling, and regular ceiling in the rest of the house, but our walls are different than the ceilings.. What color are your ceilings, they don't see colors like we do, perhaps that is an issue? You could temporarily add something to the ceilings, such as letters or colored paper pics so they see where things end. Are the walls the same color as the ceilings? That could throw them off?
They may have crash landed so much that they are now afraid to fly..it might just take some time for adjustments for them. Greys don't like change, so they may just be taking longer to figure out your new house and how to maneuver the rooms. Taking them by hand around and showing them the boundaries is all I can think of. they seem to not know them yet..be patient, and help them see what they cant figure out...my kids when teaching my amazon how to fly, would run with her and tell her to fly when he got close to the couch and allowed her to crash land there until eventually she could land on her feet on it, it gave her confidence over time to try flying elsewhere.
Please keep us posted..this is a tough one to figure out..but hoping in time, they will get it