Does the M670 not have a detachable power cable with a kettle plug ? I know some Dursts do, in which case all you need is an IEC extension lead such as the Amazon one you cite.
Alternatively cut off the two-pin plug on the enlarger and replace it with an IEC plug which fits the StopClock such as
http://www.amazon.co.uk/Kettle-Male-...ewireable+plug
We sell them too but cannot buy them in at that price, especially with free p+p!