[cypher]

How long is it now since you separated them Geewhiz? I can't remember which was the more dominant of the pair but if Goose was the one being bullied it may just take her a while to settle & gain more confidence before she begins to explore & run around more freely.
To save her stress & you money I would try to identify her needs before you make your final decision.
Do you know the size of her current bin (litres or cm) just for comparison to other cages?
If you're putting your cage on a shelf you could still use a bin cage, smaller if necessary but just make large side panels for better ventilation & interaction.