Upvote:9
You lied about your family connection on a previous application and now want to tell the truth? The ECO will wonder how much of what you are telling him can be relied upon. You are likely to be refused for this reason alone.
It will take more than a cover letter to resolve this problem. If you admit to having lied before you risk being refused on ground of deception and being banned. If you lie again and are found out you will definitely be refused and banned.
You need some serious advice from a lawyer with experience in unpicking this sort of problem. Expect this to be expensive.