Have found a summary of interrogation report of Staka 1./NAGr14 (name isn't mentioned, apparently Hptm Hans Kempe). He became a POW 4.Oct.42 and said that NAGr14 is based on airfield Mineralnyje Wody, 8 FW189, Gruko is Major von Oppen (correct info).
Interesting that he said about 1./NAGr14 though in GQM loss return the unit is 5.(H)/41 and according to
www.ww2.dk 1./NAGr14 was formed from 5.(H)/32 one year later, on 1.Dec.43.
Is it means that 1./NAG14 was unofficial designation in Oct.42 or the Staffel was renamed not 1.Dec.43 but in autumn 1942?
Best regards,
Andrey