I seriously suggest double checking you don't have faulty controls - Presumably the motor has a plug arrangement you can detach and you can get hold of a multimeter (borrow one or buy a cheapo).Thanks for the info.
I'll need to take it back to a garage. The lack of new parts is a pain.
It would have been unfortunate to replace on motor with another broken the exact same way.
First check all the pins for voltage coming from the car with the multimeter set to DC volts, negative lead to ground (engine/chassis).
Turn on the ignition/engine and have someone operate the wiper controls in turn while you test each of the pins for voltage and take notes - That should identify each pin is functioning as expected, the one where no power comes through will be ground.
You can then test for resistance on the corresponding ground pin on the motor for each of the pins for slow and fast, one will be higher resistance.
At least that way you will confirm you where the problem lies.