I think the regulator was set a bit low so I'll get a pressure gauge and test.
Could you make a crude speed controller by having a circuit with a variable resister, a capacititor then one side of a relay and a small battery (3v) then to the other side of the relay attach the motor. Then use a servo to control the variable resistor and have a simular setup for reverse?
I know it wouldn't be the best but would it work?