Remove electrical socket. Remove washer tube. Rear wiper unit held on by three aluminium rivets. Use an 8mm diameter drill bit (5/16") in a battery drill. Smaller size drill bit will not work; bigger damages plastic bush. Drill out rivet heads. Pull wiper unit out of the grommet in the glass. Carefully peel back sticky plastic cover over centre cut out. Pull tailgate down with strap and recover rivet heads.
My wiper unit was un-repairable due to washer water leakage into the works.
Nick
May 2008