Graham,
you peeked my interest, so I looked this one up on internet.
This unit seems to be for small indoor planes, one of the sites users was indicating the typical receiver range for “orangeDSM2 type receivers” was about 15 paces (less than 15 metres) so not great for pond/lake work.
My DXi6 2.4 for comparison has a range in excess of 100metres (beyond my eyesight for racing IOM).
Kimosubby