I am so sorry - that is a complete nightmare! I have heard of hamsters chewing through cage bases before. There is a thread on here by vectis about how to repair a hole in a cage base. I wouldn't use lemon juice - it's not good for them and won't stop her. She clearly wants to get out. She sounds like a very active hamster. It is a lovely big cage as well so it is nothing to do with the size. Do you think there is something about the set up that might be making her stressed? Sometimes if something is not right for them they bar chew (or in this case, base chew). Examples are - if they feel a bit exposed (seems unlikely when the Barney has a shelf and a good house), or if their wheel isn't working and they have pent up energy. Or if the wheel is a bit small for them and uncomfortable to use. Or even just to try and tell you something - eg water bottle not working and they are frantic. Or if they can't reach food and water easily.
It's a bit of a long shot but could you post a photo of her set up - there maybe some minor change that might settle her.
I know some hamsters feel stressed by too much open space above them. Our Syrian is in the Barney cage and he didn't like too much space above and always moves around the cage "under" something. So I have a couple of rat sputniks hanging from the roof and an extra shelf and he feels more secure with that as there are things above him that give some more shelter.
But simply putting something on top of the cage can do - eg a blanket - not covering it completely. I have a fleece hammock sat on top. You'd need to be careful there though as if she is really chewy she could chew it through the bars. Could you put an envelope folder/file thing or something on the top large door in the middle. It would make it darker underneath and feel less open above?
Found Vectis's info on mending holes in cages - it's on her website
https://vectishams.wordpress.com/201...oles-in-cages/