OK so I have *i think* solved the problem of the 92mm not changing speed when I try to use the fan controller. There is a short actually in the fan (on the circuit board) which means that when the LEDs are plugged in getting 12v if the fans are also plugged in then regardless of what they're meant to be getting, they get 12v through the LED wires! Dammit! No idea how to fix this, but I can see the extra little bit of solder which is trailing across the trace on the circuit board. And they're damn noisy so I really wanna be able to quiet them down.