UK Passport/Citizenship from my father?

Hi there,

I am having trouble finding information regarding my situation. I want to apply for my british passport/citizenship but am not sure if i even qualify. I did find info a few months ago pertaining to applying through your father and cant seem to find it anymore.

My situation is this:
I am a canadian citizen. My father is UK born, but he recieved his Canadian Citizenship in the mid eighties sometime....my grandfather is also UK born and lived there until he died. I did find some info saying if you were going through your father - your parents had to have been married prior to your birth - ive recently realized mine werent. They did marry afterwards.

Where do I even start to look? Id rather speak to someone but cant call the 900 numbers from my phone.

Does anyone have any ideas? Im not having any luck on any of the websites im on.

Thanks so much.