In my first post I stated:

"...
When you are happy that it does what you want, you can fix the values
in column F and then copy/paste them over the values in column D, and
then delete column F.
...."

To fix the values, you should highlight the cells with the formula in
and then click <copy, then Edit | Paste Special | Values (check) | OK
then <Enter. Now you can copy/paste these into column D to overwrite
the values there, and you can delete column F. As there are now no
formulae in operation, there is nothing for Excel to calculate, so it
should run much more quickly.

Hope this helps.

Pete

On Jan 1, 1:55*am, Colin Hayes wrote:
Hi Pete

OK that's perfect now. Thanks - I'm very grateful for your help.

It works brilliantly , and is just what I was hoping for.

Although , Excel seems to be perpetually calculating now. As I'm
applying the formula to a large number of rows , it's constantly
freezing up while it calculates and recalculates. Just switching between
sheets sets it off again. I understand why it's doing it , but wondered
if there was a way to minimise this.

Best Wishes

Colin