My grandfather is in the middle row. He joined the RAF as a boy entrant in 1920. He served in Iraq 1924-27 and India 1927-29 so I suspect by the uniforms this is from one of those postings.
I believe the plane is an Airco DH-9A.
The location may be Iraq. It looks like the RAF 55(B) Squadron: https://en.wikipedia.org/wiki/No._55_Squadron_RAF#Between_the_Wars.
On another picture I think I recognise the dog on the right in your picture (but now a bit older): https://55bomber.wordpress.com/2010/12/02/raf-55b-squadron-hinaidi-iraq/
Airco DH.9A. It served during 1920-1931 in the Middle East and India.
Same prop, prop hub, radiator, wing struts, dihedral, exhaust stacks.
I couldn't identify the thing hanging from the top right wing. Wikipedia's photo has something else hanging there, shaped more like a tiny dinghy than a fuel tank.
I couldn't identify the "triangular roundel" on the radiator, but it matches the one on the side of the nose and on the wing bottom, in Wikipedia's photo. It may indicate a theatre of operations.