Dear Sis This is Colin taken at the Braemar Gathering. Prince Arthur is standing at the back and his son is along the front with Mr Farquharson and Invercauld and Lord Aberdeen with Mr Hosie (the Factor) then the Princess Royal shaking hands and at her back Princess Arthur. Doesand (sic) Colin look nice in his car. The man in Highland dress is the man who is her attendant while at Braemar. Love to all hoping to hear from you soon. Love from Meg & Colin
His wife Princess Arthur (Princess Alexandra, Duchess of Fife in her own right, 17 May 1891 – 26 February 1959). She is the woman nearest the car.
Their only child was Alastair 9 August 1914 – 26 April 1943. He could be about 14 in the photo.
The Princess Royal is Louise the Duchess of Fife, 1867 - Jan 1931, the eldest daughter of King Edward VII and the mother of Princess Arthur. She is the one shaking hands with either Invercauld or Aberdeen.
Mr Farquharson of Invercauld is Lt Col Alexander Haldane Farquharson (1867-1936).
Lord Aberdeen is John Campbell Hamilton-Gordon 1847 - 1934.
Mr Hosie, the factor, I found in a photo of 1938. He is the factor of Mar estate and is seen with Myrtle the daughter of the above Invercauld in September 1938 possibly at the Braemar Gathering.
The date then is somewhere between 1926 and 1930, going by the birthdate of Alastair and death date of Princess Louise. ( I think it is most likely 1928 as young Alastair was there in 1928. The Princess Royal was wearing beige in 1929 and 1930 was a washout and none of the Royal Party attended.)
And the driver of the car is Colin Clark my great uncle, son of Jessie Sievwright and Charles Clark. The card is written by his wife Maggie Bella Pirie and "sis" is Colin's sister my granny.
I had previously seen the photo below but didn't know who it was. I believe it is the same car in the first photo, registration HP .. (Moral of the story - don't throw anything out!)