After all it was only a couple of dozen lines of code.
Turns out that it's one of those things I know that will never be used again; like how to hotwire a 1972 Ford Cortina, or how to get into the Tullyglass Hotel Disco for free.
Ah, for a misspent youth!
What's that? You want to know?
sudo apt-get install postgresql-8.4-postgis