Right, I’ve now found the pic that made me think of this thread again.

This was labelled as a Grahame White float plane. What struck me were the number of struts on the float and, for a WWI era float, the long streamlined design.

Also, the Wight Type 840, which has a multiple stepped hull but again more struts than normal on a seaplane.

There is also an article on the Wight Seaplane in Flight: http://www.flightglobal.com/pdfarchive/view/1914/1914%20-%200336.html

These are the closest that I’ve seen to anything resembling the mystery float. I don’t think they are conclusive by any means but intriguing.

Allan