Cheapest I found the cone inc postage recently was Ribble though Sigma look to be a few pence cheaper at the moment. I've bought from i-Ride before, but IIRC they've got a £50 threshold for free postage and highish charges otherwise.
Digging out the notes I made (Chorus hub), I've got the Campag part number as HB-RE022, same as Fulcrum R1-006. Also in a kit as Campag HB-RE100 or Fulcrum RS-100 - not sure what other bits you get though.