The most common fault for any abs light to stay on is a faulty wheelspeed sensor. If you can find the connectors for these, and have a ohm meter you can measure the resistance of them. They should all be around 1k, and depending on their temperature, they should all give more or less the same reading. If you find you have no reading on one or more sensors, then they are faulty.
Obviously, first check all the fuses are ok, and that the connections to the abs pump are clean.
Apart from that ask an autoelectrician to check the fault codes for you or if you are really desperate its off to your local Rover dealer.
Steve Eastman, February 2005