Joining lists from 3 columns

Hi,

I have three lists in separate columns that I wish to join together as 1 list in a fourth column. ie the fourth column will contain entries from list in column A, then entries from column B, then entries from Column C, going down the pages so it forms one long list.

The catch becomes the lists in the first 3 columns vary in length, as they are populated using an index and match function.

Please see attached file. Please note this is sample data only.

How do I go about generating the list I require.

Thanks, Simon