Look ya twat, grow some nuts, and grow up.
My nephew "signed away" his responsibilityies, and he's regretted it ever since.... I didn't find out until AFTER the event.... He's a changed man now, and wouldn't dream of ever doing that again, esp now he is a step dad, and a proper dad (I can tell you tho, there's no difference in the way he raises both with his wife).
If you just want access but want nothing to do with her...
1, pay CSA by DD
2, after 6 months of regular unmissed payments, go to family court for access.
3, stop going round there, and stop fighting.like a girl, like she is. Just stop it FFS, you're an adult now.
I grew up with a dad who kept pretending to be a dad, but loved n doted on his new family, while fucking me around, while I was in care. It's called... EMOTIONAL ABUSE ... A B U S E , get it.
Those kids know you're their dad, so be a fucking dad. Birthday cards, Christmas, events they ask you to attend.
Now.put down your crayons, and start acting like a dad, and stop fucking around with the kids emotions.