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So don't worry so much about how to use  had had  as a unit of grammar, they will come together naturally when you want to express the verb ' to have ' in the past perfect. Let's consider a different verb for a moment like  to want .
use been after the verb to have use being after the verb to be some writers occasionally confuse the words being and been as a rule the word been is always used after have in any form e g has had will havethe word being is never used after havebeing is used after to be in any form e g is was werese being after the verb to be some writers occasionally confuse the words being and been as a rule the word been is always used after have in any form e g has had will have the word being is never used after have being is used after to be in any form e g is was were