I now have the part, but not so fast, the clear plastic retaining part must have fallen down inside the backrest - maybe while I was waiting for the replacement part or maybe as soon as the black part fell off.
Taking the backrest cover off looks really hard - removing the whole seat and stripping the backrest off and then taking that apart.
Do you think cutting the leather between two holes and slipping the parts in would be a good idea? Maybe sewing it up or using a patch and glue?
Attachment 20933