A walk in the woods.

I have always been fascinated by this old machine which I assume is an old generator, although I am open to suggestions if anyone knows, and the old building , of which  I have no idea. 
We see them as we walk  back home from our local  Hartley woods. They are just sitting there in the grounds of some little cottages.
Hopefully one day I will see one of the residents who might be able to enlighten me.