To the earlier suggestion that it might look like a Bob Jackson, the SN isn't consistent with their numbering, so it ain't a BJ. Other than that, I got nothin'.

Other than to say that it's obviously a high-end frame, and if you have a chance to grabs its 61cm brother for 50 euro, take that chance and run. And then tell me how much you want for it plus shipping, because I ride a 61, and it would fit VERY well in my current stable, which includes a BJ, a Scapin, and an Austro-Daimler.