Thanks for the replies.
Agree omega31, I also have no complaints with the 6speed with my V6.
Yes the 6 & 7 speed are different gearboxes. But it is still not clear to me that the actual ECU unit is different & not subject to the same issues relating to electrolysis. One of the interesting things about chasing up a wide range of part numbers for any vehicle made in western Europe is just how many of them use the same part from EOM suppliers. That's not only within the VWG but other manufacturers as well. No effort wasted in reinventing the wheel for each different brand name it seems.