Anne, see this post for what should be there
http://www.bristolcars.info/forums/8...on.html#post83
My view is that you should replace the original parts, rather than using an aluminium spacer, assuming of course that they are still available from Bristol.
I have the full spring specs somewhere, because I had new ones made. I will dig them out as soon as I have some time.
Whatever you do, don't be tempted to just install longer springs!