After much searchong a load of hassle I found out how to do this.
Attached is the formula for the info of others ...
Code:
=SUMPRODUCT(--('[Home Inbound1.xls]Survey MAILINGS 2002-05'!$A$8:$A$10000>=VLOOKUP(B1,Sheet1!A:B,2,FALSE)), --('[Home Inbound1.xls]Survey MAILINGS 2002-05'!$A$8:$A$10000<=B1), '[Home Inbound1.xls]Survey MAILINGS 2002-05'!$P$8:$P$10000)