These simple metal tabs were used when fitting new front seat squab covers to most of the earlier fixed Mini seats mainly as an aid to simplify fitting. The ends, or 'bottoms' of the squab skirts have a pocket sewn in behind the facing material as shown below - the metal tab slides into this, fills the pocket, and the metal bends over the frame hooking the covers in place when the skirt ends are pulled down and the covers are fitted.

 One pack of these is enough for both front seats.