Does this come with the inner tent / ground sheet so it can be used as an additional bedroom & not just the storage?

The Annexe comes with an inner tent as standard, which, as a pod, features a built-in groundsheet. If you were to remove the inner, then it would be just grass, but you can buy a separate footprint for the annexe, which can protect the inner tent and give you a floor for when the inner isn’t used / for storage.