Hi Gonzo,
I'm sure the bluetooth thing that you're missing is the same as the one in this ad: http://www.350z-uk.com/topic/62691-bluetooth-adapter/ (Sorry it's sold, but it's the most recent one and has a good pic).
It;s common for them to be missing as they sell for £60 - £90, so are frequently removed by owners before they exchange their Zed. It sounds like you've got the cradle and everything else, it's just the plug in adaptor that's missing.
They frequently come up for sale on here in the classifieds, but it may be worth posting an ad in the wanted section as there are a few member traders that normally have them. There's always eBay too.