I entered my previous employer name and got 10 possible entries, of which 5 were "archived" and only available after a 10 day delay. I had better luck ringing round pension providers and getting them to do searches against my National Insurance number. :)
https://www.gov.uk/find-pension-contact-details
**EDIT
I just tried this, and see that the FIND MY PENSION service is dependent on your knowing the details of the fucking pension you are looking for.