Had??

I'm looking over the documents you/you've sent.

Because there is no call for past perfect.

Can you explain why you can't use "had"?

There is no second, more recent past event. That is the minimum requirement for past perfect.

Hi

I am also learning here.

Can I say that "had" cannot be used here because the sentence itself seems to be a conversational speech than a reported speech?

i think I learnt this for other forumers that use "had" when one of these conditions:

1) two actions in the past. Like what you just explained

2) use in a "reporting" type writing i.e. reported spee

Can I say that "had" cannot be used here because the sentence itself seems to be a conversational speech than a reported speech?-- That is one use of the past perfect, but you cannot say it of the given sentence because that is not the reason for its incorrectness.

I am unfamiliar with your #3. Is that not just one instance of #4 (Conditional III)?

Hmm, yes you are right #3 and #4 are the same.

Thank you very much.