Marsden
Whilst there is plenty of water at the site, most of it is captured in resevoirs which top up the canal (a 3 mile canal tunnel runs more or less under the property, and this is the high point of the canal too - so the reservoirs top up the canal in either direction). The water that is not captured in the reservoir doesn't flow down just one channel either - there are several small streams and springs on or near the property, none of which really have sufficient flow to power a house. If all the streams were directed into one channel, and sufficient head (10 metres or more) were available, then this could be a viable off grid site - however the land surrounding the property doesn't allow for that.
Whilst a small, seasonal hydro scheme could provide power to a battery-tied off grid system for several months of the year, in drier months this wouldn't be available, which unfortunately means that a hydro system would not be a practical primary power supply. As such, hydro is still feasible to trickle charge (500 watts output for example) a battery system, however another source (wind, solar, generator or the grid) would be needed.