Right well, I just took the side panels off and disconnected the actuators and the problem is gone. I think it was the drivers-side actuator as it is stiff, smells like stagnant water (probably why it's not working).
Although, I cannot seem to get the thing out to take a look at the actuator so I can clean it. It's connected by only some sort of wire or connector leading behind the security panels (which I can't remove at the moment as I can't find my spanner!).
Still need to fix the wipers though...
