Rich Stone wrote:
Thanks for your reply. Could you possibly explain how I would do this? I'm
afraid my excel skills don't stretch too far in this aspect and I've never
used pivot tables.

Besides the link already provided by Dave, you can also look here for
introductions to PivotTables:

http://peltiertech.com/Excel/Pivots/pivotstart.htm

Check them out and see if you can work it out. They are not that difficult.
Otherwise, without a lot more information about your worksheet layout, it would
be difficult to help further.