Hi, folks...
From the LEMB website on 07/07/2011, where Peter Evans has supplied some excellent e-bay listings...
These three link to a Do17 which clearly shows a 'Z5' code. Is this perchance the machine in question?
http://cgi.ebay.de/Orig-Foto-Flugzeu...-/140573668992
http://cgi.ebay.de/Orig-Foto-Flugzeu...-/130542391787
http://cgi.ebay.de/Orig-Foto-Flugzeu...-/140573669007
Regards,
Paul