What about "Port Elizabeth in Bygone Days" by JJ Redgrave. Amazon and Abebooks both have it, though it is expensive at $35. I've not read it myself so can't say how appropriate it us.
You can see some details here:
http://books.google.com/books?id=64IwAAAAIAAJ&q=Port+Elizabeth+in+Bygone+Days&dq=Port+Elizabeth+in+Bygone+Days&pgis=1Iain