Thanks for your response. Yes there have been different methods of populating this table. As Jeff said one of the methods is broken and needs to be fixed. I will post up a different thread once I get a chance to take a crack at writing code to properly update a SCD table. If any one had any links/sample code on this that would be appreciated.

My original post was looking for a one-off fix and what I posted subsequently seems adequate so i will do what is pragmatic and move on. The existing broken process is not broken in the sense that the data is incorrect but rather it is always inserting records rather than updating which resulted in performance problems. My one-off fix should not destroy any data, all the information should be preserved just represented by a smaller set of records. Thanks all.