Ok now this is interesting. The bank one is green the bank to is red pre cat bright post cat dark.
I was already going to replace 2-2 because it was already reading funny compared to the just replaced 1-2 but now it's just stuck at 0.4v.
(Could be because it actually does have a failed heater )
Anyhow after this "test run" noticing the drastic difference between the old and new sensor readings I will replace in pre/post pairs.