problem with a countif or sumproduct formula

HI

trying to work out a formula that looks at a cell, finds the ref in another sheets, checks a column and adds up all the dates that are within 6 months.

I have tried "SUMPRODUCT((VLOOKUP(A5,Data!A3:G6,7,0)<H3)*1)" where H3 is a date.

If have tried countif but is does not seem to like having to look for a "lesser than" value if it's a date ?

Anyhelp would be much appreciated.

I have uploaded the sheets I'm working on. Very basic at moment.

thanks

Mickeyp