binrow, We had a similar problem on a 733 a couple of months ago, although I wasn't involved in the job, I got the full story from a couple of LAE's who did work it, and what transpired was that after numerous cable inspections, lots of rigging checks, various component changes to try and resolve the out of limit spoiler extensions, the LAE's involved on the job decided it was due to the lever not moving back far enough, ie, you weren't getting full deployment on the ground, with this in mind they gained access to the centre pedestal and turned the stop fitting around (full extend) and hey presto snag cured! they believe this snag eminated from Boeing!
Hope this may help you!?