Sturmey Archer S2C/S2

Some friends and I did a group buy of 6 S2Cs last fall. 4 out of the 4 built up units regularly experience mis-shifts, one of the hubs innards completely imploded. 2 of these are regularly used in commuting, 2 are occasionally used. I'm attempting to return mine.
Buyer beware.

I've been running the SC duomatic for about 6 months. It now fails to engage the lower ratio so Im stuck with the cruising 78.
I've just read this - http://mccraw.co.uk/sturmey-archer-s2c/
So anyone out there any ideas on who/where to fix this ?