Hi Graham, Stace3 is the standard naming and the UKSI follows it very closely but sadly (and confusingly!) the NHM's copy of the UKSI on the website is very out of date. I'm currently trying to get it updated but I have to work through other techies and we're having difficulty finding the expertise and the time to get it done. If you'd like to check anything then you're very welcome to try out my sandbox/development site: http://nbn-sd-dev.nhm.ac.uk/
Chris Raper, Manager of the UK Species Inventory, Angela Marmont Centre for UK Biodiversity,
Natural History Museum, Cromwell Road, London, SW7 5BD. (tel: 020 7942 5894)
also Tachinid Recording Scheme (http://tachinidae.org.uk/)