So I picked up this photo at lunchtime today from a junk shop for just 70 pence. And the reason I was drawn to it, apart from the fact that I simply love photos of old interiors, is that at first glance it seemed to show really clearly how cabinet photos were used in display.
But one of the wonders of the digital age is the ability to scan things at high resolution and see into the details of the photo. With the naked eye I noticed that there was a photo on the wall behind the photographer reflected in the mirror. On closer inspection it becomes clear that this is a sporting team and, because I've seen a lot of them, I can tell you it's the kind of sporting team photo that you got from rather posh schools with hand-written calligraphy and heraldry on the mount.
This then, suddenly makes sense of the fact that the cabinet photos along the mantle are clearly not a family, they are all young men of about the same age, some of them wearing what can only be an academic mortar boards and many of them, once you are able to look closely, are signed. I had hoped to date the photo from the ceramics because the jug on the mantle is Royal Doulton Dutch Harlem which was produced in the 1880s and certainly there isn't much in the room that doesn't look like it could have been from that period, but then the scan revealed the writing on the trophy cup. Although most of the writing is unclear I am sure it is dated 1914. I also wondered if another of the words on the cup might be Harrow so, returning to the photo in the mirror, and remembering that it is reversed, it's clear that the crest is indeed for Harrow school. It was then I remembered that I have before come across the tradition of the men in a big public school house signing their photos and, though I can't rule out it happens elsewhere, that was at Harrow too.
So, what do we have? My best guess is a housemaster's study where the house trophies are kept. Who is DM? I don't know, presumably the initials of a house master at the school but that's where my research is going to close.
...still, not a bad bit of entertainment for 75p!