Gathering a shopping list at the moment for Jaycar when I get a chance to go in soon. The kit number is different to the Dick Smith one quoted in the tutorial. I think the Jaycar equivalent one is
KC-5225 "10A 12VDC Motor Speed Controller".
I'm looking into the replacement for the trimpot as recommended by Alan. Looking in the Jaycar catalogue for potentiometers there are 2 different types of 24mm PCB mounting ones. "Log single gang (A)" and "Linear single gang (B)". Which one is correct? ie
RP-3608 or
RP-3508?