Unfortunately it was a one off, I think.

It's obviously been used on something like a golf buggy, but apart from being a little bit short it's ideal, as the  spring eyes are on the top side of the spring.
It just means I have to sort spring hangers on the beam, rather than the swivel mounts at the ends.

There are also some nifty grease nipples in the bushes  that I could do with replacing, but the bushes are good, and it just needs a bit of cleaning up. 
The other advantage is that I can adjust spring rate by taking leaves out as required.

Peter