Subreport not showing all data

I'm new to CR2008 & subreports and I need to add a sub report to my main report so I can provide more detailed information. My linking field is a customer reference no, all I get in the sub report the last record from my main report.

I've tried doing this as a simple report with only one table and the same happens.

What am I doing wrong?

Thanks :)

What section is the subreport in? How did you do the linking?