Nellist - Exact Location
Well it looks like you were on the right track with Winchester Terrace. Checking the location you went to and the address in my earlier posting shows you were only two streets out. The attached picture is a map showing Winchester Terrace with a star on it, and I have drawn a rather crude circle around where Summerhill Terrace is. It is not printed on this map for some reason but I verified it from my copy of Autoroute.
Hope you make it back there OK!