Mamerle,
Thank you for the serial nos and details, most useful.
Yes the aircraft listed are all Fairchild Argus. The type was supplied from the U.S.A. and purchased with Lend-Lease funds. Those delivered to the U.K. were extensively used as taxi aircraft by the A.T.A. Thus, A.T.A. logbooks are a rich source of Argus records.
After delivering an aircraft from the factory or a repair unit to it's allotted squadron, etc, the A.T.A. crew would be required to return to their Ferry Pool as soon as possible for the next assignment. The purpose of the Argus four seat taxi aircraft was to make that return journey as quickly as possible, the railways being over-pressed with the movement of many servicemen. Ansons and Dominie were also used for this taxi role. There is clear evidence from your mother's records that the Argus were also used for training.
White Waltham was the H.Q. of the Air Transport Auxiliary and also the location of No. 1 Ferry Pilots Pool.
Luton may relate to No.5 Ferry Pilots Pool, which originated as the A.T.A. (Womens Section) at Hatfield and moved to Luton in April 1942.
My source book ("RAF Flying Training and Support Units since 1912" - Sturtivant and Hamlin) does not specifically list any unit at Barton but No.14 Ferry Pilots Pool at Ringway would not be far away.
Hope this helps, M-62A3