Well done!!! Enjoy the rest of your life!!!
I don't fully agree as I believe preparation in the form of background revision of current knowledge and what you're expect to know did help me, as all bases were covered and that gave me extra confidence in examination that I wouldn't be tripped up by lack of knowledge of a basic detail.
However, the viva is very much about opinions as you're being examined about material that is new to the subject area. Scripted answers don't help with cutting edge research as much of an area can still be up for debate and discussion.
Ian (Mackem_Beefy)