That is fantastic advice, nickle.

Dogs and children together require very close supervision and a lot of training (for both, like nickle said). It is well worth it if you've put the effort in. I can't see how someone else training the dog would help, because a great deal of a dog's responsiveness comes from being trained by you. While our dog will respond to everyone in our family, there is no doubt that I am the one he obeys and responds to best, because I am the one who put the hours of training into him. And he's just a pet, so that basically entailed sitting, coming, lying down, a few tricks, good behaviour on the lead and with other dogs, family rules around kids toys, etc, etc. We had him from one year of age, and like nickle's dog, he wasn't mature until two. It is like having a child in the house before then (except you don't have to take them everywhere with you!). He has no other job but to be our family dog, not our guard dog. TBH, I can't really see how guard dog and family dog go together at all. You're looking for gentleness and a lack of (ready) aggression in a family dog, which is completely contradictory to why you need a guard dog.

Have a think about why you need a guard dog. Often just having a dog around will provide a level of security (they bark, will still alert you if anyone comes onto your property, can be somewhat protective of their family, just aren't trained to 'guard'). Most intruders are put off by any dog being on a property. If, on the other hand, you are truly after a security guard level of protection, then you'll probably need a dog that is not closely involved with your family. Is there any other kind of security you would consider instead (ie alarm, security guard?).