Decided to come back for a last look...is it the FVA-2 Blaue Maus
Ditto, to see if there were any answers
!
It is indeed the
FVA-2 Blaue Maus 
Well, it was a development of the FV-1, they are very similar (and I think some of the photos may be mis-labelled)!!
Natty construction involved:
Very interesting article on it's designer, quite an extraordinary career
Wolfgang Klemperer - Wikipedia, the free encyclopedia
skytrain10 has control Edited to say skytrain has requested an Open House. Sleep well 