Transform an horizontal table in vertical (3 columns) with Power Query

Hi LukeReds 

Give this a go. It assumes the same set of three columns is repeated in the exact same order.

let
    Source = YourTable,
    Split = Table.Combine( 
        List.Transform( 
            List.Split( Table.ColumnNames(Source), 3 ), each [
                t = Table.SelectColumns(Source, _),
                v = List.Last( Table.ColumnNames(t)),
                r = Table.FromColumns( 
                    List.RemoveLastN( Table.ToColumns(t), 1) 
                    & {List.Repeat( {v}, Table.RowCount(t))},
                    {"Name", "Description", "Date"}
                )
            ][r] 
        )
    )
in
    Split

with this result

I hope this is helpful