Pair of black vinyl windscreen "A" post pillar covers. Special order, lead time required.
From the manufacturer:
99% of all Minis had painted "A" post pillars in body colour. We have developed a kit (pair) that fits exactly in this space with the least amount of fitting. A fibreboard panel covered in black vinyl material has double sided tape on the reverse side. This piece is adhered to the "A" post and a flap on the outer side is held in place by the door seal on the post.
Instructions:
Simply peel the tape off the double sided tape, place, turn over the body flange and replace the rubber door seal.