Update: this in from a PPHP reader
I am doing some work on a photograph which was taken by this agency.
I think it was run by Charles Henry Park, who worked from 89 Fleet Street.
He is listed in the Newspaper Press Directory and Advertisers Guide 1917 with this entry:
“Park’s Press Photographic Agency, Limited. Topical photographs from all parts of the world and news stories will illustrations. Advertising and commercial photography a speciality. Address – 89 Fleet Street, London E. C. Telephone Holborn 2019”
If you have any info on this agency please email firstname.lastname@example.org