Does anybody know exactly what checks are made at the London embassy once you have sent in your forms from packet 3?

I'm not sure I understand what you're asking. Security checks? Checks to see if your forms are all filled out correctly?

Sorry what i should of said is... security checks... when am i ever going to learn that people cannot read my mind lol

I think most of the checks are done from state side, But London wil require you to take a Police certificate with you to the interview, this is a security check of sorts