Land Rover RKB 101111 coil springs (Brown/Purple).  These are used in the rear of Defender 110s from VIN 159807 (TD5 and up)

A kind soul has measured these up.  They have 8.8 coils each using 19.1 mm bar.  The inside diameter is 135 mm.  Free length is 381 mm.  The upper 2.5 coils are at a variable tighter pitch than the rest of the spring.  I calculate this gives a rate of around 270 lbs/in initially.  This will increase to around 420 lb/in once the tight coils are all touching.