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.

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.

However, one of the many innovative products produced by WaterMota in the initial years was a variable pitch propeller which could be set to allow speed, ahead, astern and neutral by altering the propeller’s pitch. This was a much improved version of the original variable pitch propeller thought to have been patented in 1895 and was in production until the late 1990s. The outbreak of the First World War severely curtailed the production of marine engines with production facilities given over to making Hyland Cocking levers for machine guns and a range of aircraft fittings."

Below, an advertizing blotter ...

1920 - article from Indian Industries and Power, Volume 17

Cheap Outboard Motors
Owing to the high price of marine motors, increasing use is now being made of the little outboard motors which can be attached to almost any type of craft at a low cost and driven at a moderate speed. The employment of these little engines should become. more general in India, for, with a little ingenuity, they can be attached to all classes of existing boats, and as the petrol consumption is very low the cost of operation is almost negligible. 

In the illustration is shown a 3 1/2 h.p. Watermota, the only British-built engine of this class, built by Walter D. Fair & Co., of Hampton Wick, Middlesex. It is fitted to an ordinary Thames punt which it drives at a speed of 5 to 6 miles an hour and is a remarkably good production selling at the relatively low price of  £50 complete.

Usually the outboard motor is attached to the stern of a boat by means of clamping screws, but in the case of a punt a square hole is cut in the deck at the after~end and the motor is then attached in the usual way. It can be readily removed in two or three minutes so that it does not detract from the value of the boat when the motor is not required. There is a single-cylinder horizontal engine driving a vertical shaft,at the bottom of which the drive is taken to the propeller through bevel gearing, the rudder being attached to the casing in which is contained the vertical shaft. The whole unit is therefore very compact, easily portable and eminently suited for employment on upcountry rivers.