Graeme,Most importantly look in skins/default-results.html .
But really you should use a text editor and replace it in every file where it occurs, not just the default. I'd do a search for 1925 (Kurt's ID) and replace it with your own. You can use Windows Explorer Search if you need it. I count 10 files total that need updating, all ending with an .html extension.
The 1925 will occur as part of a searchfeed.com query string, and just to be safe, you may want to visually check each occurrence of 1925 before changing it.
Jeff