Cheers GW that one made more sense.
The people im getting it from cant help, they just sell them, pretty sure somewhere near will be right enough, i’m a keen moto trial rider and ride one of the few single pivot bikes ever made the Scorpa SY, i just set rebound to just under springy and ride, i compete regulaly and do well. I got the Heckler as the rear end feels identical to the Scorpa, im hoping that once its somewhere near spring rate i can just adjust the rebound to suit, for the money the shock will cost (sub £100) i will take a chance if a can figure out roughly what spring is needed.