If you want to keep your early Mini original, this door seal is the one to use. Fits either side. Black solid rubber u-channel, with hollow foam seal section that flattens to fit. Fits all Minis with sliding windows including Mk1 & Mk2 Sedan, Van, Pickup, and Wagons. This seal will take a while to compress down to its final dimension, and initially will make the doors resist closing and seating fully. Sold each.
See also XGA9934V as an alternative seal for this application.