There are no more updates from nokia or vodafone. Click on the cssu update (top right on this page) and choose the stable flavour.
I am wondering how you have a "NEW" "UK Vodaphone" N900 but aren't English? It seems amazing there are new ones at all for starters. Anyway I believe Vodaphone UK had there own firmware image. You are best to completely reflash the device to Global firmware and then install CSSU-S (Stable) as explained in the links below. http://wiki.maemo.org/Reflash http://wiki.maemo.org/CSSU