Hi @silverdarling
When working with sub fields, you will need to use the approach shown in the http://www.advancedcustomfields.com/resources/tutorials/querying-the-database-for-repeater-sub-field-values/ tutorial.
This is because the field_name saved in the dataabse requires a LIKE lookup due to the changing row number in each name.
Hope that makes sense mate.
Thanks
E