[INM@RLM]

THANK YOU, Nick. All MOST, most interesting and very much appreciated. Your database is working well.

V.(Z)/LG 1 - to start with the easiest case
Some context on ULTRA CX/JQ/89. There were three different airfields named St. Marie in use by the Luftwaffe at this point. The information in Eimannsberger is detailed from logbooks and shows V.(Z)/LG 1 at St.Marie-Chevigny throughout the period 20th to 28th May. (This is indeed the St.Marie north of Neufchateau.) So the first part of this message to my eyes looks to be about resolving a confusion between which was the actual St.Marie in question. The second part of the message is absolutely accurate regarding the current base move which was to Le Mans on the day after the 27th June date of this message. (All locations are as I stated above.)
CX/JQ/100 also aligns with what I wrote above. It is also prima facie evidence that throughout this period V.(Z)/LG 1 was operating under the command of Stab/ZG 76.
So the V.(Z)/LG 1 case is clear and corroborates what I already set out.

ZG 26
I think it is easy now to see the origin of the confusions in this period regarding Barly (not Barley), Yvrench and Crécy-en-Ponthieu, all so neatly set out in CX/JQ/108 of 3rd July. All are valid but these are actually the bases of occupation for ZG 26 at the end of the campaign in the west. So all of ZG 26 was indeed incontrovertibly still in France in early July, but the combat record still evidences that only III./ZG 26 was allocated to Lfl. 2's Kanalkampf force in this period and for this it was based at the newly completed airfield at St.Omer-Arques (Fort-Rouge). As anyone can verify, Arques in the Pas de Calais was far, far closer to the Straights of Dover, whereas the bases noted for ZG 26 on the 3rd July are all well to the south in Picardy and also very much further inland from the Channel. The balance of the Geschwader was evidently non-operational at this time. CX/JQ/102 is then a pointer to a large part of this Geschwader being subsequently transferred from France back to Germany a little later in July.

ZG 2
Particularly intriguing. There was definitely an intent then to employ ZG 2 operationally in France in the first half of July. However although we have these and one other early sign of preparations for such a deployment, there is absolutely no evidence that any of this actually happened before the end of that month, and no evidence of any combat use before the August dates I mentioned.
We know a lot about most of the aircraft on the strength of ZG 2 in the first half of August 1940, and quite a number of them were from Messerschmitt's June deliveries of a very new variant. That and the initial deployment of ZG 2 c. the start of August to the Paris area (Toussus-le-Noble & Guyancourt) rather than Normandy, suggest (a) throughout July there were still insufficient forward airfields to make use of ZG 2 with its current equipment, and (b) the decision was instead made to upgrade the Geschwader as far as possible with early examples of the very new Bf 110 D-0, Rüstzustand II (the variant fitted to carry underwing drop tanks instead of a Dackelbauch).

Most helpful. More breadrumbs still needed though.