I gambled wrong, it is the 30mm hub.
From searches on the forum, plus asking members which they had, I've only heard of the gti using 30mm
So mark 5 golf GTI DSG 05 reg - 30mm hub.
I personally think mark 5 GTI use 30mm hubs. Perhaps other models of golf (TDI, GT, R32) use others. Could be wrong but ive seen four or five GTIs using 30mm hubs, with none using 32mm.
Hopefully helps someone in future
And some extra key word searches :) Rear hub bearing 32mm 30mm