Ok i've read through a number of the sumproduct solutions to this type of
question but i'm still yet to find one that works in this case.

I have a worksheet that contains data about product rentals. To simplify the
example I have 3 columns as below for temporary fencing hire. One row is for
each customer:

Meters hired        Hire Date          Return Date
12                       24/07/2007           7/08/2007
87                       15/10/2007          19/10/2007
72                       14/12/2007          17/12/2007
25.5                       22/06/2007         22/12/2007
30                         7/12/2007           1/02/2008

Now I want to set up a function that will tell me how many meters I had out
on hire (total) in say November 2007.

Thankyou in advance for any assistance!