My father was not able to make the signing of my birth certificate when I was born, so only my mothers name is on it. My mum has now passed away and I would really like my fathers name on there. Could anyone tell me if this is possible and if so how to go about it?

Depends on where you live. Any question of law needs to include your general locale.

Has your father been declared your legal father by a court?

I live in England. And no. I don't think he has ever been listed or what ever as my father. Maybe for child benefit but that's it.

And have you discussed this with him and he is willing to do it, if the courts will allow ?

You need to check with the registry of births for your district to see what the rules are.

Yes I have spoken to him about it, obviously he would love to be on it... he is my father (I think :P)