I'm fairly sure that to accurately DNA test you need the parents. I think you are talking about the DNA tests they have now which can "apparently" tell you what breeds of dog your xbred dog is. Many people have had these done and then posted the results up on various forums and they appear to be a crock of you know what!! Wouldn't waste my money thats for sure. I also could not see it being able to be used in court.
The Council don't need to prove its a pittyx as Teebs has stated it is chipped as one.