The National Army Museum have seen the photo, and stated "The dignitary seated left of centre is Arthur, Duke of Connaught". Prince Arthur was Queen Victoria's seventh child, and held various military ranks including field-marshal, dying in 1942 aged 90. I think you will agree he looks about 70 in this photo.
The two soldiers are seated in the centre front row of a posed group photo of 30 people, ten of whom are in uniform. Civilians include Rudyard Kipling, his wife, and their daughter and son-in-law. I am trying to identify the event that these 30 people were attending: it seems to have been taken between 1920-1930, and may well have involved an equine event such as showjumping - another photo in the album (of a relative) is labelled "Summerdown Eastbourne 1920" and shows a uniformed rider (also present in the group photo) about to leap his horse over a fence/water jump. Sadly the group photo is not labelled.
So your help would be much appreciated! I gather the Prince and Kipling were friends, and corresponded regularly. I am trying to identify other persons in the photo to help identify the year/event.
Thanks in anticipation of your help