1999 1.4 focus had a knock sensor fault with itreplaced it and now its doing the same thing and a fault is coming up of p1000 and cant whip the fault off it?

The P1000 DTC in the case of Ford vehicles means that the OBD-II moniter testing is not complete. It is minor. You can safely ignore this code. It will clear as part of normal driving. A few drive cycles should do it.