Hey Mark 1 problem I'm having is on startup. I can have the circuit turned on, with the output set for zero, and the mosfet drain supply is turned off. The LM358 is on max output. Then hitting the power switch for the drain supply, the current often jumps really high, and around a bit in general and doesn't respond at all to the poti. setting. That's alarming, I had my PSU limitied to 0.5A and is jumped right to it.
Once I can get it settled down, then it behaves fine, and seems very steady and low noise, at static loads.
So the last 2 times I started it with the gate unconnected, aka connected to the external input switch. Just about to troubleshoot a 12V 5A SMPS brick for a monitor, so I'm hesitant to connect the load tester, in case it shoots to max.
For now, I only added a current limit of down to 70% max of any setting, just using the other 1/2 the opamp. I should change it down to near zero%.