Wayne

Many thanks for your help here. I will take a look at the X3 ones you posted. It's crazy that a common consumer part cannot be easily found by a main dealer and several different parts guys all searching the BMW systems?

They are absolutely adamant that what has happened is that the screw in rivets they have sold me now are 'replacement' parts for the sprung half turn rivets that were on the car? I am not convinced by that as they just about fit where the screw thread only just catches the retainer, meaning that any slight pressure would allow the whole thing to come apart again.

Here is what they have given me:

51 71 1 947 438 PUSH BUTTON
51 71 1 947 419 NUT