Yeah, that's an odd duck. Those 7 holes in the bottom bracket are kind of characteristic for a Windsor Professional (which this certainly is not). The workmanship looks decent, but not what I'd expect from a top level builder. Those large fishmouth seatstay ends stand out particularly. It looks like they weren't mitered correctly, so the dropout sits too far inside, with the opening not centered on the dropout leg. Maybe a project from a frame building class?