...AMS-NWI-AMS flights are offered for around 230EUR (that is KL fleecing the Dutch customer base).
It certainly seems that the folks at KLM don't really like Dutch pax: NWI-AMS-NWI for early/mid March (1 week r/t) comes out at 122GBP, but AMS-NWI-AMS on the same dates is 218EUR.
But I agree - unless you have a specific reason to fly KL (in which case, LCY is a lot easier than LHR: 40 mins to Kings X then ~45 mins to Cambridge), then EZ is cheaper and considerably more convenient ... other than the 'indignity' of being spotted by other FTers as you make your way sheepishly to Schiphol's LCC gates!
-- Henry