[INM@RLM]

At the risk of becoming marked as an obsessive in the matter of the early Ju 88 Cs, forgive me if I also register three niggles here. This in the hope that those working on future histories of the Ju 88 fighters will lay out answers that are considerably clearer and indeed may hopefully be recognized as definitive.

1. It is curious to see the old mislead of the Ju 88 V7 possibly being a Ju 88 Zerstörer Versuchsmaschine being given one more airing here on p.9. More than 30 years ago it could be deduced from Manfred Griehl's account of the Ju 88 that this was the confusion of a V-number with a Werk-Nummer, since Griehl established that the first Ju 88 Zerstörer Versuchsmaschine was in fact the Ju 88 V15 (aka 'Z15'), for which the airframe assigned was WNr. 0007, & Stkz. DD+IA.
Ju 88 WNr. 0098, CN+NR is also identified here on p.9 by one author as "the first Ju 88 C production aircraft", and then on p.53 by the other author as "the first prototype C-1 (W.Nr.0096, coded CN+NR)". Way back in 1970 this was the aircraft that William Green identified as the "Ju 88 C V1 alias Ju 88 V7" in his Warplanes of the Third Reich.
I have found no documents to support this, but the case seems to be that CN+NR was WNr. 0098, not 0096, and this aircraft was nothing more than an Erprobungsträger, and accordingly was never assigned a V-Nummer. This airframe simply served temporarily as the flying test bed and proof-of-concept aircraft used to establish the optimum arrangement for the fixed forward-firing armament, ammunition cans and feeds, and the forward armoured bulkhead, prior to JFM beginning design of the streamlined metal nose cone for the Ju 88 fighter derivative.
Since doubts have now been reintroduced on both points it would be a step forward to see each explained explicitly and definitively in some future account.

2. All unit codes ascribed to Ju 88 C fighters lost during the Norwegian campaign are stated here to have been assigned in the 4D+_H series. This indeed follows a long tradition. That Zerstörerstaffel/KG 30 would apply in parallel the exact same codes as those already in use by 1./KG 30 is - to these eyes - highly problematic, especially when the 4D+_Z code block was eminently convenient, completely logical, and without overlap of any other part of KG 30.
Since the individual aircraft identity letters used with the known 4D+_Z codes seem initially to have also all been assigned wholly from the second half of the alphabet, it was hardly possible to distinguish these Z.Sta. aircraft more clearly within KG 30.
What still needs an explanation though is why after Norway there are confirmations of some Ju 88 C-1s bearing 4D+_H codes whilst the 4D+_Z codes were also still in use. Twenty-one Ju 88 Cs had been delivered by the end of April 1940 and even after losing six there were still more than sufficient to equip a single Staffel. Thus it is conceivable that a Kette of Ju 88 fighters was assigned directly to 1./KG 30. However, for the present the mystery of why two KG 30 unit code allocations were in use simultaneously on Ju 88 Cs is simply ignored and hence has yet to be explored.

3. The Schatz photo at the foot of p.56 is a lot more interesting than the captioneers noticed. It is described here as portraying "a line up of KG 30 Ju 88 Cs". This it most assuredly is not. The two all-black Ju 88 Cs nearest the camera are clearly fitted with the longer A-5 wing and bear the 4. Staffel codes ??+FM and ??+CM. That is about as good evidence as one might ever find to confirm that these are the aircraft of 4./NJG 1 photographed presumably at Düsseldorf and most probably in the earlier part of the period mid-July to mid-September 1940 (at which point the unit was redesignated as 1./NJG 2). [A number of dates have been given for the formation of this second iteration of II./NJG 1, but the Einsatzbereitsschaft in BA-MA RL 2-III/708 (available online for download) explicitly evidences that the change took place after the 13th of July and before the 20th of July. Hence 15-Jul-40 is about as close as we can currently get to an effective date for the creation of this formation by redesignation.]
These all-black aircraft can only be Ju 88 C-2s (the first being delivered in April 1940 and then 12, 5, 1, 1, across the four months June to September 1940). Indeed, looking at the Einsatzbereitsschaft reports for the second half of July 1940 this photograph may have captured the whole of the serviceable part of the initial complement of 4./NJG 1.
The third aircraft from the camera with the RLM 70/71 over 65 finish, is assuredly a Ju 88 C-1 since the characteristic tip of the A-1 wing fitted to this airframe can be seen clearly outlined against the sky. The code of this machine was (imj) undoubtedly 4D+UZ and it was either WNr. 0137 itself or numbered very close to this identity. A close review of the original print may reveal more than can be distinguished in this reproduction, including a conclusive identification of the airfield.

But enough.