Hi Roger,

Thanks for the suggestion, but that puts the characters NOP in the cell
(H4), whereas the first time through it is populated with the reference
number and there-after I dont want it to change. That formula
overwrites my reference # with NOP. Assembler had the useful facility
to do a compare and, if required carry out no action as one of the
results

If A1 = 0 Then
Now() puts in the date/time stamp as a number (acting as a reference
#)
Else NOP no action taken, leaves the contents of the reference number
cell as is.

But thanks for replying

Regards
Fred