The current Watermota Company's website gives a succinct history. They aren't interested in going into details or sharing early photos though!
The early history is this:
"Watermota was established at the Pembroke Engineering Works at Hampton Wick, Kingston upon Thames in 1911 by Walter Fair as a subsidiary of Rigbys, a London gunsmith, where he was the manager."
"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."
"During the First World War, the British Admiralty approached Watermota to design and produce an outboard for their use, the result being the Mark 1 which was produced with little change until 1926 when it was developed for outboard racing for Fair’s son Colin and Shingo Yano who had previously worked for the Anzani engine company."
