How do I get rid if the ABS fault light in the dash of a VW polo 2003 any suggestions short of replacing the expensive ABS pump unit?

You will need to run a diagnostics test on it. If you don't have one take it to a garage to reset it.

It may well be faulty but most of the time its just dirty sensors that result in a misreading ECU. Another common fault is the 40amp fuse on the ABS circuit - this is under the bonnet next to the battery, NOT in the dashboard fusebox. After a number of years this can crack, leading to an intermittent loss of power to the ABS pump (which the ECU if read will report as an ABS Hydraulic Pump failure). So check all the strip fuses there and replace if necessary. Note that even if it's something simple like the fuse, you may still need to reset the ABS warning light either at a garage or with your own diagnostic tool if you have one.