score:9
I can't find any record of Richard Garriott's (or parents') address in Cambridge, and I don't think it is a very large city, so the fact that he walked to Prof. Hawking's house does not say much.
But from this Cambridgeshire County Council page about births, marriages and deaths you can make a search for the birth certificate of Richard Garriott, born 1961 in Cambridge, which turns up the record shown below. I can't see the actual record (you can buy a copy) but my own UK birth certificate records the address where my parents were living.