abs problem?

Hi .

My Mk4 Mondeo had been showing an ABS light. I took it to KwikFit for diagnostics and it showed as n/s/r sensor fault.

Once replaced the light stayed on so they suggested changing the hub/bearing.

Again once changed and road tested the light stayed on and the diagnostic would not re-set the light.

Im really stuck (and so were they) as to what the problem could be.

Any advise would be priceless please.

Thank you in advance

Adrian