[INM@RLM]

Stig, you were right to be cautious.
There are two French communes named Barly: Barly (Barly, 80600, Somme halfway between Abbeville and Arras, so about 40 km from each) and Barly (Barly, 62810, Pas-de Calais further east well towards Arras). However, during the BoB both were always in the Luftflotte 2 area.
Barly, 62810, Somme is I believe the one with the BoB Feldflugplatz, the same Barly that was apparently used by III./ZG 26 from around early Aug until Nov-40.
Along with Yvrench (I./ZG 26) and Crécy-en-Ponthieu (II./ZG 26), this Barly is between the rivers Somme (to the south) and the Canche (on the north), all these airfields lying close to the valley of the River Authie running between the two boundary rivers. This looks an entirely logical grouping for a full ZG deployment, using Absprungplätze nearer the coast to actually launch missions.
The De Zeng Airfields Listing for France gives the Barly, 62810, Pas-de Calais location ("landing ground in NE France 17 km W of Arras"). In the context of the other ZG 26 airfields of this period that looks like it needs adjusting. Perhaps there is some archaeological evidence to throw definitive light on this?