Would not have found it without the hints. It's the Yomiuri Y-1.
Flight has it from 1956? http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%201576.html
Going to press on here with a lumbering (or should that be slumbering?) beast...

Flight has it from 1956? http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%201576.html
Going to press on here with a lumbering (or should that be slumbering?) beast...