Arne Vodder Desk screw/bolt query  

We have this Arne Vodder Desk and are have misplaced the fixings that hold it together after it being in storage.  We've tried a couple but don't want to damage the top and wonder if anyone could shed any light on what might work!  

They're the ones that attach the main desk piece to the base.  

I've emailed a couple of dealers online with the same desk but Pamono wouldn't help as we weren't interested in buying and not heard from the other one.  Also emailed Sibast but they don't hold info on the earlier Arne Vodder pieces.

Any assistance gratefully received. 🙂