My Citroen C3 has ABS and when l break it judders for the first few seconds then seems to kick fully.My garage says that is how ABS works but it really vibrates, so things in the car all bounce about,l am sure it is not meant to do it that much is it???Also they feel quite 'scrapey' but l had new break pads a couple of months ago.

ABS should only be used under hard breaking. normal breaking should not cause the ABS system to kick in. you may have a bad sensor, or even control module. and the ABS should not cause your car to shudder, it should just make your break pedal to fluxuate.

the abs only works when u are skidding..if its working every time u use brake its broken,,[no matter what the idiot mechanic sez].cauld be wheel sensor..[abt 100 dollars] or abs .brain [compuiter [1200] dollars..i had sensor go bad and it grabed my brake every time l got to 5 mph,,

It sounds more like your front discs causing brake judder rather than an ABS problem.
The ABS should only cut in when the brakes are pressed very hard, however the discs, if slightly distorted would cause this problem whenever you brake.
The only solution is a new set of discs.

What the ABS is does is simply ''inserting'' pauses into braking. You floor the brake pedal, but the ABS is releasing brake pads from the discs for a few milliseconds at a time. That prevents wheels from locking. The same aplies for braking in wet or on snow/ice. It feels like somebody is kicking you at the right foot.
If you experience vibrations under normal braking and you're sure it is coming from the brake pedal, there is something wrong with the brake discs.

Have the brakes checked properly, sounds to me like you have warped or damaged brake discs. Remember also some C3 is have disc brakes at the rear as well (the higher spec models with the 1.6 petrol or 1.6 16v HDi engines usually).