Thanks guys for all your input
I've been observing this for my entire time on the 320 (2.5years) pretty well after every landing with any pronounced crosswind (>10kt ish, DRY or WET), whether I use MED or LOW autobrake doesn't seem to make any difference to the fact. I believe I do see it even when I kick out Autobrake prematurely (to roll through to the end etc).
So here's the fact compiled from all your comments
Downwind wing, after touchdown, produces less lift, therefore, Downwind side gear has more WEIGHT on it
Now, this "sort of" makes sense to my dim brain, as more weight means more loads on the wheel bearings therefore more heat being produced...
My original guess was that autobrake was modulating and differentiating left and right gear brake pressure after touchdown to compensate for the wind, but I guess that was too wild a guess! 