On putting new pads in my brakes part of the process requires removal of the circlip and pins to get the pads out.

A very fiddly process.  The circlip is very small and has a tendency to want to fly.

However I noticed very worryingly the steel pins had corroded. And when the corrosion was removed with brake cleaner and a nylon tooth brush the grove in the pin was too large to hold the circlip!!

As you can see on the left hand pin above(the used pin) it has an enlarged slot for the circlip. It is so large the circlip just falls off and you therefore need to use a new pin.

However my concern is around the fact that this probably means the circlip was only held in place by corrosion. This doesn't seem a very good design idea nor a very safe construction. BMW have no interest in this problem.