ECSL not showing invoice for one customer

Hi

My ECSL for April/May/June doesn't match the value of EU sales on my VAT return.  The ECSL has one EU customer missing (having one invoice).

The customer and the invoice are both T4.

The country code is "GR" for Greece (although altering this to another included country doesn't make any difference).

The date range on both reports is definitely the same.

Has anyone else had this or got any ideas?

Thanks in advance.

Karen