Hi , When you say ABS light on the speedo is not working do you mean it never comes on
even before you start it with ignition on , if thats the case I would assume some 'cowboy' has removed the bulb to mask an ABS fault ( you wouldn't believe the lengths some people will go to to pass NCT without spending money , fine on non safety critical items but Dangerous on ABS and Airbags etc ). if light comes on with ignition and does not go off shortly after start I would assume either a wiring fault or ABS unit failure or fault , quiet common fault on R50 .
G