I've dealt with this in the united states. In an attempt to keep them from invading my property, I secured all fencing with locks, and basically blanketed the damn place with "No Trespassing" signs. I kid you not, they just climbed the fences to get to us with their trite little lectures and interrogations. It's probably the same where you are: they get paid a commission for taking each child, AND they have a quota. And so much more, which you've likely learned about at this point. This is a very dark place, where these twisted creatures dwell.
Now... I'm not going to give this as advice, but rather, just tell you what I did. I played dumb and submissive to assuage their power trip while I secretly planned. Then... I got the fuck out of town and made myself as untraceable as possible. Since I'm in the U.S., I was able to go to another, far away state.
We are vax refusers, and I suspect it put us on a list, because my baby was a newborn still when they started with their shit. I'm very intuitive, and knew with total certainty that they were definitely going to take him if I didn't do something kind of drastic like that.
It worked.
In the end, it was almost a blessing. It took force for me to make a big move like that happen, and where I am is much more free, with lots of parents who pass on the shots and public schooling with no problems.
RE: Update: Standing my ground against Child Protective Services - They're showing their true colours