White plastic/nylon buffer on door of all UK external hinge minis.
The door striker plate 14A6832 holds the door shut, but the nylon guide block actually supports the weight when the door is closed. When one wears it typically takes the other with it, so replace both. Dont foget to replace the plate 14A6834 that sits in the recess which protects the buffer from screw damage.
The original bracket that the screws fixed to is no longer available and Heritage do not drill the doors, therefore the choice is yours No6 self tap (not advised) or drill the door and use a nut and bolt. The original screws for this are 6/32"unc and part number CMZ212.