The photo was taken by Henry Taunt, who died in 1922. He was quite a well known photographer.
The original copyright would have been with him and his heritors for 70 years after his death.
See:
http://www.rootschat.com/links/01qfn/
Henry Taunt began his photographic career as assistant to the first commercial photographer in Oxford. He later set up business on his own account.
Henry W. Taunt & Co., publishers, artists, photographers, picture frame manufacturers. Shop in Broad St., Oxford. Lost lease on his shop in 1894 and filed for bankruptcy. After discharge from bankruptcy he began to work from home on ideas for books and guides documenting counties surrounding Oxfordshire.
He had no children. His housekeeper was the main beneficiary of his will. Following Taunt's death, many of his glass slides were destroyed by the purchaser of his house. An Oxford librarian/archivist rescued surviving slides, negatives and photos.
Majority of Taunt's surviving images are held by English Heritage and Oxfordshire County Council.
Editors of the photo journal "Picture Post" may have paid a licensing fee to one of those organisations or to whoever held the copyright, depending on copyright law at the time. "Picture Post" was published 1938-1957.
There was an exhibition "In the Footsteps of Henry Taunt". The associated website has a photo of Taunt's shop.