A great story. Every household should have a Carster - mine could do with one for sure. Not that he'd ever seriously consider working for the likes of me. He'd probably think even Galpie is too good for that.
I loved the way you spread the story both over the day and over the year, and the Albus/Filius glimpses we get. And Albus who's always had a thing for blond - such a great tie-in to canon.
The Downton Abbey layer is beautifully done. Loved this whole story. Great job.