Thanks to Vanessa for this photo. She writes:
thought you might like to have this photo for gwulo. i have never seen it before, neither did i know that DBS had an interim campus between bonham road and argyle street.
I haven't seen this one before either - Nathan Road in the foreground looks like a country lane, with piles of rocks and weeds growing.
The AMO's notes have some more background:
Although completed in 1925, the Old Kowloon Police Headquarters was not occupied by the Police until 1932. From 1926 to 1932 it was used as temporary premises by the Diocesan Boy’s School (拔萃男書院).
I've guessed the date of the photo is 1926, based on the rough appearance of the road.