Customer Spend Report - 365 days

I'm trying to run a report to show total spend for each customer for the past 12 months. DEAR support keeps giving me suggestions but they don't give me the full picture of what each customer has purchased, regardless of whether payment is outstanding or not. 

The Sale Invoices & Credit Notes seems the right report but I can't get 1 line per customer but rather total per customer - this makes it hard to sort?