Heater Blower issues - 2003 A6 - have replaced motor...

I'm having an issue with the blowers in my car and I need help understanding what I'm finding. For reference it is a 2003 A6, 2.7t and is a Right Hand Drive. It has dual climate control. It also has a solar sunroof which I've seen is a possible fault cause too.

When they stopped working I hit up google and found that the most likely thing was the blower motor/resistor (am I right in thinking the resistor is contained in the housing of the motor?). So I bought a second hand one off eBay described as "in good working order" and fitted it. Easy job, didn't take too long. Still no blowers though. So I borrowed a multimeter and checked the only connection to the fan, which was showing 11ish volts. So I assumed that the second blower unit I had bought was also faulty. But I did some more digging and found that the voltage at the connector is the same regardless of the fan setting on the climate control unit. Indeed, the connector gets the same voltage with the climate control unit off but with the key in the accessory position. So I have realised that I know dangerously close to nothing about how this all works.

My questions are this:

1. Given the 12v at the connector and no movement from the fan, is it likely that the second blower motor is also gone in some way? Or does it activate some other way.
2. Is the voltage staying the same regardless of settings correct, or is there a fault somewhere else?
3. If the solar sunroof relay was the problem, would the connector still show 12v? Is that something worth changing?

Additionally, I notice that there's a motor, that I assume changes vane positions to direct air flow, that operates when I turn the climate control unit on. It seems to be making a clicking sound - is this of note?

Thanks in advance