Create List using values in Filter drop down

Hi everyone,

this is a tricky one but i'm sure its possible.

I would like to create a list in my sheet called ("Lists") from the unique values in the advanced filter dropdown menu in cell ("L1") on the sheet called ("Sheet30"). The name of the filed is called "Root Cause".

This must be do-able i'm sure one of you whizzes has a way of doing this, if i could have the basic code i will adapt it to suit my specfic needs.

Thanks for reading and for any help that's offered.