that will mean the model will have gone through trmendous currents on its way down, and i am not sure how deep lake dinorwic is, also as its the lower lake to the pump storage system, i wander if the model has or could be sucked up into the turbines when the lake is pumped to the top of the mountain to replenish the header lake (which during generating times emptied totally)
polaris, sad as it may seem and i do not wish to offend anyone, i think that in this case, andy wright is probably correct, 160ft is deep and borderline for scuba, tied in with the currents generated by the pump- storage system of the power station, it may be in a dangerous diving area.