clio central locking problems

hi hope someone can give me a clue as to whats happening here, i have a renault clio expression 52 reg and have been having problems with the central locking,the problem is that every now and then the central locking goes crazy locking and unlocking itself it can go for weeks without doing it then all of a sudden it will start,on occasions the button for the locks doesn't work but then on other occasions it will work,i've also noticed that the boot never locks at all if anyone can point me into the right direction i would be grateful.

thanks people

clio central locking problems