Hi Stig,
Thanks for the response. I've has some more time to think about the first photo since posting. As you recognise the style of serial may be significant in identify the aircraft shown and the full serial.I suspect we both have the same photo of A.13/13 and I'd agree its probably a different machine.
I'm not sure if you've got P.M. Grosz's WDF 104 but having looked at it again, it has a photo of A.10/12 which looks much more archaic than the aircraft here. So I'm inclined to think the machine is either /13 or /14.Looking at the style of serial I thought that it looked not unlike the photo of Gotha LE.2 on Kees Kort's flicker page at :
https://www.flickr.com/photos/varese2002/32400077541 Also, while Tauben resemble each other I thought that this LE.2 resembles the second machine in my post - alas the crash has disfigured the front end of the machine in the first photo, but if it is the same type of Taube, or even the same Taube, might it be an LE.2? and A.13/14 or possibly A.15/14. I have no definite identifications for either of those serials, so it may be possible.
Regards,
Clint