I doubt that these components are interchangeable and as I said previously cant see that the spring length alone will make much difference to wheel camber. It sounds to me that, assuming the spring is correctly mounted, you have one that has had an easy life and not flattened out much. However if youre worried about the positive camber (not so much of a problem with a swing spring car) then as Clive says a lowering block or more tools/spares in the boot will help correct it.