Thanks Colin, yes i've worked out now the car has to be 06 plate or earlier,the tax saving is'nt the be all and end all to me ... it's more of a my money and the Gov not getting it.
An example here
http://www.350z-uk.com/topic/98247-black-06-350z-only-32k-3-owners-fnsh-v-original-rays-spare-oem-wheels-8000-ovno/