So if I connected it backwards by mistake (i.e. batt + to source), the gate and source may both be positive and the thing might turn on? Or am I misunderstanding there?

Would I be more successful using a high power standard (bipolar) transistor? (as I tried the same experiment with some unspecified transistor and the same thing happened) - would it even need to be high power?

Cheers

-- Stupid Kev