Ju 87B-1 Stuka with outsize overwing crosses

[Seahawk]

I have an old Almark sheet with markings for 2 Ju 87B-1s of StG51 (code 6G) in late 1939 ie after Poland but before the campaign in the west.  They are distinctive in having massive white outline crosses applied to the upper wings, in addition to the small early standard upperwing crosses.  These were apparently introduced to address misidentification problems encountered in the Poland campaign but were quickly superseded by enlarged upper wing crosses of the size most people will be familiar with.

 

The research for the Almark sheet was by Les Whitehouse so I am pretty confident in the accuracy of the markings but would still like to see some photographic evidence.  So far I have drawn a blank from Smith: Stuka At War (Ian Allen), Weal: Junkers Ju 87 Stukageschwader 1937-41 (Osprey), Smith: Luftwaffe Ju 87 Divebomber Units 1939-1941 (Classic Colours) and Junkers Ju 87 Stuka (MBI).  Can anyone help me?