£40 for the parts and do the labour your self, really not that hard.
take door card off.
undo some screws to detach the inner regulator pannel.
using a tripple square tool, which can be bought for less than a 5er, undo the door lock module (one screw)
take out the door barrels (they just slip out)
undo a screw and the regulator pannel should come off.
slide the clips out (presuming the clips are broke) and slip the new ones in.
then do all of the above in reverse.
first time i did it it took me two hours (but i left the clip on so once i was putting the door card on realised so had to take it all apart again and also forgot to take one of the old clips out so again had to take the door apart again) if i didnt have do do that ide say it would take a hour.