Thanks, I double checked this... pulled the blower and took it apart, cleaned the brush area (quite dirty), squirted some CLP on the bearings and put back together. Caught the noise again after, it is definitely not blower motor, definitely outside the car and coming from the front. Chattering, chirping, rhythmic squeak from under the front of the car.
Honestly I am about 80% sure it is the electric fan. The fan does make a chirp when spinning down. It doesn't seem quite loud enough to be able to break into this, which seems quite loud. A bystander would hear it if they were in their yard I think, and probably think I need a belt or brakes.
I just can't piece together the whole story of if it is the fan, how does it chirp so intermittently, only at vehicle speed and mostly when warming up? What is the logic of the fan; from what I can tell it is two speeds. Is it ever OFF completely? I could see the wind being a factor influencing the noise of a fan bearing at a low fan speed of if the fan were off.
Thoughts? (Thanks so much for the reply)