Hi Damien,
If you go with DC motor, make sure the dynamic braking is implemented, like in my version (
Post #2 in this thead).
This is to avoid motor overshoot, it may be annoying with bigger motors.
I solved this with electronics... you can use QPDT switch and suitable wiring (I didn't have it at hand then). I have the 9V battery inside housing for 10 years, and it is still OK.