Ok – short and sweet. I needed to do a search in AD – simple enough – but I wasn't sure where I'd have a code example for it and I haven't done it enough to write it off the top of my head. I checked in my "TestApplication" project – a console application where I do all test development, creating a public class for a particular area of development and writing static methods so I can quickly call them from program.cs. I went straight to "AD.cs" (with my fingers crossed that it was some search code) and there it was – equipped with a bunch of useful test code ready to go. The moral of the story is – do all your "not quite sure about this" development in a test app (which is quicker to test that SharePoint and you can change your code at runtime) then when you need to do it again in 3 months time, the code will be there, ready and waiting. Wonderful.