This question contains spoilers…
(view spoiler)[I don't understand why Rose is a "secret orphan"? Surely, young, innocent 7 year old orphan's whose dead parents were spies wouldn't be prosecuted. Is there any evidence to show that governments went after orphaned children of spies? (hide spoiler)]
Here on the West Coast, (USA) many Japanese were sent to camps, because they were considered "enemy" even though many were American born. In England, any Germans would have been treated with suspicion & hostility. That is War.