As a preventative measure I have repacked my rear struts and fitted grease nipples. Its quite an easy job, in fact the hardest part was removing the bottom nut from the strut, had to make some mods. I used Lucas Red n tacky grease
HERE that I got from ebay. But to be honest any good grease will do the job. I would recommend fitting grease nipples as you can then fill the chamber between the bushings.