i need a part for my defender 90 door lock. On the end of the barrel there is a middle part that comes off when you push in the small brass button, you then transfer this bit to a new barrel and the fin part goes on the end and is fixed with a screw in the end and this bit attaches to the wire going to the latch. Very few people seem to know what this is let alone what it is called and does not show on the pdf parts layout. I have tried lots of places but they are all confused. The only reason i know it comes off is a gut at britcar who strips landys down knew.