Ok so I noticed by accident the other night that the rear heater/vent between the back seats extending from the center console was blowing cold. I thought it was because the little temperature wheel was set to cold (blue) instead of hot (red) so adjusted and didn't really notice any difference.
I checked the front vents and they are fine, and even turned the A/C to blow directly out of the dash vents only to see if that improved things and it didn't.
Any ideas? :s