I used the following extract from BOL ms-help://MS.SQLCC.v9/MS.SQLSVR.v9.en/udb9/html/7b28942f-252b-4448-88bc-dedbe53b0a82.htm (Changing Rows with Positioned Operations - Performing Positioned Updates with APIs) to kinda-guess the right answer.

"After positioning in the cursor, execute an UPDATE or DELETE statement with a WHERE CURRENT OF clause referencing the name returned by SQLGetCursorName. But this method is not recommended. Instead, it is better to use the positioned update functions in the ODBC API."

Was it a fluke, or is it some indirect help from BOL? Or maybe direct help - cursors are a bit of a *gasp* grey area for me!