Thanks but this doesnt quite do what I wanted.

I need the serial number to include the initials, ie JB for joe bloggs PK for phil kennedy etc.

I have had an idea but I need to figure out a way to do it.

I know that you can copy cells to a txt file.

At the moment I have a list with all of my order numbers in (PK00001 - PK60000 or something :-) )

Is there a way, of copying the value used to a text file, then searching for and deleting that value from my list for next time

For example, if PK00001 is used, the value is copied to the txt file, then the value is searched for in the sheet and deleted.

Next the sheet is saved, this way the same number cant be used twice and once you have used 100+ numbers you dont spend ages searching through a lst.