The electrics in Lagunas aren't the best, from experience, so if the motor is good, but working woefully, then the voltage to it isn't the best. Everything in the car is powered by relay, so maybe you have a burnt out relay, in that circuit? Or the wiring isn't earthed correctly?
Test the motor via an external source, check the earths. And check the owners club, some allow you to post a taster question for free, and then you have to pay up to join, but my limited experience of Lagunas, is that they have a history of electrical failures. Checking the owners club might reveal a common issue?
I know how frustrating it is to receive drip drip information...but fingers crossed for you.