Damn it. Why did i not realise that That's VERY possible.
As a bonded pair though, won't they share new territory they find? I thought thats how it works, perhaps i've perceived it wrongly?
I guess i could try and neutralise upstairs as best i can with a bit of vinegar water and a quick wash of the carpet? :?
If they find it together, then yes, but if they find it separately, then not necessarily because they still are territorial animals.
He's been up there a lot without her which may mean he views it as his. would be worth a try neutralising it.