Hi Jillos, I hope you've sorted it by now and not too expensive!!
I have just posted on 'Repairing an ABS Ring' and while it's not simple, it's not that hard to do with a socket set and a few other bits if you or a friend doesn't mind dirty nails!
Bottom line, you don't necessarily need a new drive shaft and you CAN buy the rings on line (fleabay!) for less than £15!
My symptoms? Well, besides the leaking sunroof and pool in the footwell (sorted using the Betta Windscreens post on here)and the intermittent non starting though turning over (sorted, I hope, by removing and cleaning the contacts of the
Sensor under the pipe below the airfilterbox on what is now my daughters ' 03 Clio) the ABS warning light was on on the dash. The front offside wheel gave off a light graunching noise when the brakes were applied at lowish speed, especially when turning right, coupled with a more noticeable 'judder' through the brake pedal from the ABS.
Looking underneath the wheel arch, behind the brake disc, there is a cogged (toothed) 'ring' mounted on the hub just infront of the rubber 'boot' covering the Constant Velocity Joint (CV boot) on the end of the drive shaft.
Have a look at this ring. Is it broken? Jack up the wheel and you can rotate it to check it out. If it is, needs replacing!
Is it dirty/greasy? Get a degreasing spray or similar and clean it and the, by now obvious, sensor, above it. The sensor is mounted on the back of the bracket above it and has a small plastic coated wire leading down to it.
That clean may be enough.
I know this is simplistic but I'm a DIYer who resents paying a lot of money to garages to do stuff that if I pull my finger out I can do myself, with a lot of help from the peeps on here!!
Hope this helps