I am not a legal expert but I think you should put your son first.
It must have been a big upheaval for him, as well as for you, when your marriage broke up.
It's good that you are seeing him again, take it slowly and build up your relationship with him.
What a shame that you don't have better contact with your family.
Maybe you could talk to Relate
http://www.relate.org.uk/. They will know about the legal and the emotional side of things. They offer a confidential service so you will be able to go into more detail than you might want to on a public forum. We don't even know how old your son is (a year is a long time for a baby).
Hope it goes well for both of you.