Thanks Hamish...
The pond is a man made affair with run-off from the hill entering it at one end, and a dam at the other. Any excess water exits a 6" pipe as a "water fall" that drops around 11 feet onto gravel, that then soaks away. There is a land drain beneath the gravel "splash pad" that leads under the road and then into a soak away.
The water used to be used for the cattle, being pumped to the cattle sheds, but a new system was installed, taking water direct from a spring closer to the sheds, which ensures supply through the winter.
There is a possibility of buying said "pond", which is about 3/4 of an acre and "adding it to my garden".
Naturally, I would want to stock it.
The sticking point seems to be the inflow/outflow. Inflow is from a spring/run off and is approx. 250 yards long from source to pond. Outflow ends in a soak away.