Repeater Lens Door Pillar 710581/2RMK Remanufactured. These are the earlier less curved version as fitted to most MKI & early MKII.
These hand made reproductions use material that is more brittle than the originals.
Care should be taken not to squeeze the sides, or overtighten the screw. Advise using a 3 mm / 1/8" pop rivet washer with the retaining screw.
Does not fit MK1 to MB40699 1963- 64 which used an open ended lens 615012/3