Thanks for all the posts and the info. Looks like I do have a GT6 spring fitted after a second look. I want to get on the road for a bit and see how the car feels, now that the weather is hopefully going to improve. It also has adjustable shocks, which when I brought it were set quite stiff, so I will try some different settings on these.
Ian, when you had the leaf(leaves) manufactured can I ask how you specified the requirements and where did you add the leaf?
Thanks Bob