Hi @Bassscape
Your above query will only find posts (that is if the query works as expected) that have Concept and Design selected as the value.
To allow for a value within the array, you shoudl take a look at the checkbox docs:
http://www.advancedcustomfields.com/resources/field-types/checkbox/
On that page, you will see how to use a LIKE statment in the meta_query to match a value.
I have not yet combined this with a sub field DB search, but it must be possible with SQL.
Good luck mate
Cheers
E
