My daughters have never met my biological father and they never will, although unlike your situation they do still have four grandparents.

I agree with Traveller in that first and foremost, how will you feel. Do you want to try and build an ongoing relationship? If you do, then my suggestion would be that you work on that first withut Bilby's involvement. She may be lonely at not having grandparents, but it would I imagine be far worse for her to have the dream of one oh so close and then disappear if things didn't work out.

You made the decision not to have contact for a reason. As a general rule, and certainly in my case, having children now makes it all the more important to remember those reasons and maintain the distance. Miss I and Miss E know that I have another dad out there, as well as a brother and that they have another cousin, but for the time being they accept their lack of contact with them due to them being "a long way away". When they are older I will explain it to them, and my reasons for the decisions I have made.

Is there an old people's home anywhere near you? I know when I took my eldest to visit my grandmother when she was in one all the other oldies loved it too. So many of them are very lonely with no family of their own, so while they wouldn't be Bilby's true grandparents, she could form some nice relationships.