Matt Pennington wrote:
I have used autofilter to refine data now I need to number the rows - can
this be done automatically or does it need to be done after each filter is
selected?

One way:

Assuming you have headers in row 1 and data in row 2:1000 and columns B:D, put
the following in A2 and copy down as needed:

=SUBTOTAL(3,$B$2:B2)