At any rate, no luck. I thought the pictures on the wall will be a help, but no, I looked up several guesses, but the only thing getting vaguely close is Kalmy in Sri Lanka (which has a lake, one that could be vaguely surmised on the second photo behind the girl, which is partly covered by a column). The window height closes out most of the tropics, except mountain railways, but it's too wide for narrow-gauge. But it is also too wide and hassomehow  too flat a roof to be British. But placing it in continental Europe doesn't make any sense during WWII. Maybe after, in Switzerland?

Where is Helen when we need her?

_{*Lunatic*, n.
One whose delusions are out of fashion.}