Welcome back, PJ, missed ya! Really enjoyed these posts, and the best part was being presented with an aeronautical mystery, which required two ice cubes, three fingers of Larceny, and a pleasant hour's rummaging about in my Great War aviation library. Tough assignment, but once more into the breach and all that. Anyway, sometimes the oldies but goodies are the ones you should check first, so I started with my precious original copy of
Jane’s 1919, moved on to the Putnam books, and finally ended up leafing through what’s probably my favorite all-around favorite WWI aviation book, the Harleyford
Marine Aircraft of the 1914-1918 War. It was listed under Norman Thompson (the company was renamed from White & Thompson Ltd. in October, 1915), and you’ve got a good eye, it says
The Company held licence to build Curtiss aircraft, and while they both had the typical configuration of Curtiss flying boats, they were completely re-designed with e.g. R.A.F. No. 6 Section wings in place of Curtiss wings...
And that top bird is only one serial number off yours.
Dutch