I've snapped two pinch bolts and got the following recent response from santa cruz UK….
"That seems quite unfortunate. There was a slight issue with some of the original bolts that were fitted having too slim a head on them but we have replacements here with a far thicker head. I'll send two in the post to you. Just pop them in with a medium loctite on the threads and make sure the pivot axle and aforementioned bolts are tightened to the appropriate torque settings and you should have no more problems"
Nice of them to send me new screws straight away, but they are shorter (threaded bit) that the ones I had in and I'm not overly convinced by the explaination.