So, I've been reading more and more into this and, if I understand correctly, the MOSFET is limiting the current to the LED based on the voltage applied to the gate.
Therefore I will need to replace it with one that limits the same amount with the same gate voltage applied otherwise, I risk blowing the LED.. am I correct in thinking this way?
If this IS how it's working, how do I work out how much current is being limited when the LED is on?