Block exemption legislation means it is illegal for Ford to insist on their parts being fitted by their dealers. However you have a Noble so I am unclear on the law but I would suspect it's much the same. You bought a Ford part, used it as intended and it failed. To me it's clear cut and should be replaced.
So to your point what Ford told you is illegal and perhaps you should remind them of the 2002 Block Exemption legislation so they can correct their data...