Here's a pic:

The R14 is the only resistor I see and doesn't appear to have anything to do with current, though it could. I didn't measure it. Typically current carrying resistors are big, but it could be a current sense resistor.

Best thing is to do what you can to the springs and LED wires. I think Martin measured 3.6 amps so that's pretty good and also explains the stock LED turning blue. It's probably the best you can get out of this driver. It could very well be FET based, but it's a small 3 legged FET perhaps.