I suggest that one of these goes through. (Meta questions only)
1: Above "The question in one sentence" add
"Notice: Please check our useful posts on the right before posting, your question may have an answer!"
2: "Before proceeding, please check your question was not already asked" is replaced with the useful posts.
(JS, I think the Useful posts is kinda shrouded by everything else. IMO it should go on top.)