You've probably checked that there's no Barstow in the Bn roll in Thirty Days to Dunkirk - which makes sense if he'd been attached to the staff. There is a Capt J M O Barstow with A Coy 1 R IR F in Tunisia who was blinded during a local counterattack on 18 Jan 1943.
Also Viewing Page 3375 of Issue 37635 SUPPLEMENT TO THE LONDON GAZETTE, 2 JULY, 1946 R Ir. Fus (War Subs Lt-Col ) H S. P. BARSTOW (38676). who is also mentioned in the RIrF 1943 gazette LENNON WYLIE We are out of touch with the following and would be grateful for news and address:- Barstow, H. S. P.
Barstow HSP is mentioned as a temporary CO around Jan 1950, but it wasn't clear that he was 'one of their own'. Now we have a choice!
What exactly was his correct job title ? Advanced Headquarters Officer ? He seems to have 'been sent to' a lot.
Must be HSP, John Michael Orpen BARSTOW (143432) was only commissioned as a 2/Lt in Aug 1940 It looks like Att Offr Q which would be Attached Officer Quartermaster [Branch], probably no real role other than to do what he's told.