I don't know if the law in NI is different from England, but you do need to make sure you know the legal position there and don't just assume English HE sites advice will cover you - up here in Scotland the law is different from England, and we have to do things differently to keep ourselves right legally.
But, so long as you have done what you are legally required to do, there is no more reason for SS to get involved with you than there would be with a family where the children are at school. The "extra" thing for you compared with a schooling family is just that you have to be prepared to show how you are providing a suitable education. That's all.
I suspect that the families you have heard of where children were taken into care will have been families where there were a lot of problems with the family not looking after the children, and just trying to hide by not taking them to school, but not giving them any education at home either. It probably isn't a big number of families, but likely your local press have decided to make a big deal about a small number of cases.
We home educated for 2 years, and the council never once got in touch with us to ask what we were doing, even though we had phoned them several times before we started to make sure we were doing what we needed to for the legal side, and gave them all our details.
Up here, if they did have a problem with the education we were providing, they'd have to get in touch to tell us what the problem was, and give us a chance to sort it out. Only if we wouldn't/couldn't sort out the issues, they'd then ave had to take us to court and convince the court that we weren't doing enough education - only then would they be able to order the child back to school. And absolutely none of this would involve SS, just the council education department.
HTH