I learned something new today. Maybe I should have known if I had read all the small print. I confess to feeling slightly embarrassed that I didn't realise BUT given I have just had to spend several hours re-doing someone's EOI, I thought I would share. If you have previously submitted an EOI for SMC and for whatever reason it failed, was refused or not selected, you have to create a new login before creating a new EOI. Nothing stops you from completing a new one on your old login - except that when it is all complete, checked, validated and you are ready to submit, there is no "Submit" button. The answer is there in the Knowledge Base http://dol.govt.nz/immigration/knowledgebase/item/1095, but as I didn't know it was going to be a problem until I reached this point I had never thought to look! I hope this saves someone else from the same waste of time and effort.