Lets suppose that you want the last numeric entry from row 3...

=LOOKUP(9.99999999999999E+307,3:3)

would yield that entry if row 3 is not empty.

If you replace LOOKUP with MATCH in the above formula, you will get the
position of the last numeric entry.

If you want the value from row 1 which is associated with the last
numeric entry in row 3...

=LOOKUP(9.99999999999999E+307,3:3,1:1)

Put up in terms of exact ranges, e.e.,:

=LOOKUP(9.99999999999999E+307,C3:Z3)

=MATCH(9.99999999999999E+307,C3:Z3)

=LOOKUP(9.99999999999999E+307,C3:Z3,C1:Z1)

Carolyn Bennett wrote:
[...]
I don't suppose you would now know how to now that I have worked out what
the last entry in the in the row is, how I can tell it to reference the cell
two cells vertically above it?
[...]