Thanks for the reply, i tried it but i did not quite work well as i had few cost centres missing in my new list and one (just one though) was duplicated. May be i had done it wrong, i did the following;
1) Clk copy to another location
2) Clk on List range and select the colum with the cost centres.
3) criteria ??? i did not do anything as i don't know what it does.
4)Then i clk copy to and selected a new colum
If there are some missing you didn't select all the records before filtering. If there seem to be duplicates they are not really the same. For example one might have a trailing space, or one is a number and the other is text that looks like a number.