Replace null values with table header

[Martin sherk]

I have a power query table that consists of 2 queries appended together, I added two blank rows between each table to separate them from each other, now how can I replace the nulls in the blank row with the table headers?

let
    Source = Table.Combine({#"PAY only", #"REC only", #"with Diff"}),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Remarks", type text}}),
    #"Duplicated Column" = Table.DuplicateColumn(#"Changed Type", "Remarks", "Remarks - Copy"),
    Custom1 = #"Duplicated Column",
    #"Removed Other Columns" = Table.SelectColumns(Custom1,{"Remarks - Copy"}),
    #"Removed Duplicates" = Table.Distinct(#"Removed Other Columns"),
    #"Added Index" = Table.AddIndexColumn(#"Removed Duplicates", "Index", 0, 1, Int64.Type),
    #"Added Index1" = Table.AddIndexColumn(#"Added Index", "Index.1", 2, 1, Int64.Type),
    #"Appended Query" = Table.Combine({Custom1, #"Added Index",#"Added Index1"}),
    #"Sorted Rows" = Table.Sort(#"Appended Query",{{"Remarks - Copy", Order.Ascending}, {"Index", Order.Ascending}, {"Index.1", Order.Ascending}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Sorted Rows",{"Remarks - Copy", "Index", "Index.1"})
in
    #"Removed Columns1"