That R601 is a pretty good price but it does appear to be only the captain's "single speed" crank not including the stoker's crank or bottom brackets.
At current currency exchange rate and price of $261.47, the Stronglight appears to be a really good value for a tandem square taper crank. Still need bottom brackets though.
http://www.sjscycles.co.uk/stronglig...gecurrency=usd