Pembroke Engineering Works
Hampton Wick, Kingston upon Thames
I had always assumed the Watermota was a Waterman sold in Great Britain, but Peter Hunn's book leads me to think it was a rip off instead, or as Hunn diplomatically phrases it, "a clone of the 1916 forward-pointing cylinder Waterman". There is interesting (and sort of sad) information on Walter D. Fair & Co. in Hunn's book.
Remember, Waterman first produced an outboard motor in 1906.
The following info, copied from the web ( http://www.watermota.ltd.uk/) leaves me thinking there was a license agreement for outboards.
"Watermota, 1911 est.
The first engines produced by the company were American Waterman two stroke inboard and outboard engines built under licence, similar in appearance to the copper jacketed K1 and K2 engines which were eventually developed by Fair.
Below, an advertizing blotter ...