Nonnie, Meyoo is right, there's nothing you can do because you really are damned if you do and damned if you don't.
The only control you have is over your own life and that is demonstrated by the decisions and choices you make. There may come a time when you decide that you will no longer be a pawn in their game. You then need to consider what price you may well have to pay and if you can afford it.
For all estranged GP's who established a real and loving relationship with their GC, I cannot imagine what it would be like to put your foot down knowing that for that one act, you may never see your GC again.
We never had that level of relationship with our eldest GC and when his brother was born, contact had already been severed. Walking away wasn't easy, we walked away from our son who we adored and a GC we barely knew. I realise that it would have been much harder if we'd developed a relationship with our GC, but I'm as sure as I can be that we'd have still made the same decision, as spending the rest of our lives, never knowing from one week to the next if we were going to see our S and GC was not the way we wanted to spend the rest of our lives.
Should we do nothing and allow our AC to deny their children, our GC their legal right to a family life? Yes, I think we should because what can we do? We never had a relationship with our GC, something that a GP has to prove in court, so court wouldn't have been an option for us anyway.
For those GP's who can prove that established relationship, they may be successful in obtaining the court's permission to see their GC but then what? What happens if the parents don't make your GC available? You have to go back to court because the reality is, if they don't want you to see your GC, it's going to be extremely difficult to make it happen.
Starlady as you say, the actions of someone jumping in and out of someones life when they feel like it, can appear to be narcissistic even though they're wanting to try again, but a narcissist isn't interested in trying again at a relationship, the only interests they have are what that relationship can do for them, and whether or not they are the most important person in that relationship. They have to be more important than their own parents, their partner, their in laws and sadly in some cases even their own children.
Everyone who doesn't give them precisely what they want, when they want it is disposable.
BE WARNED - M&S account holders
Fabric conditioners - are they a con?