I have a very similar case to indigo_child.
The default was recorded as of October 2006 and after 6 months the debt was transferd to a collection agency. Under the threat of getting a CCJ, I agreed to make payments to clear the outstanding amount of £100 a month. As the rest of my history is now virtualy perfect, I have still been making the payments so as not to damage my credit history again.
By reading your replies on this thread, would I be correct in assuming that I need no longer to make payments after November 2012, by simply sending a SB letter?