Hi Nick,
I think that I have found another picture of this aircraft with the ridge in the background.
If so, to my eye the
werknummer seems to be 140108 which turns out to be a Rechlin-based test Arado that was sent to Neuburg am Donau to be used as a two-seat aircraft carrying an observer to the viability of the
deichselschlepp (rigid-pole method of towing) of the SG 5041. It was tested there in February and March 1945 by pilot Herr Erich Klockner.
http://forum.12oclockhigh.net/album....pictureid=1274
However, this is what it should look like:
http://forum.12oclockhigh.net/album....pictureid=1275
Jim