Tabulating Source Data using Power Query

Please try

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    SplitbyDelimiter = Table.SplitColumn(Table.TransformColumnTypes(Source, {{"STOCK CODE", type text}}, "en-US"), "STOCK CODE", Splitter.SplitTextByEachDelimiter({": "}, QuoteStyle.Csv, true), {"STOCK CODE", "No"}),
    AddedOutlet = Table.AddColumn(SplitbyDelimiter, "OUTLET CODE", each if [STOCK CODE] = "OUTLETCODE " then [No] else null),
    AddedBuyer = Table.AddColumn(AddedOutlet, "BUYER NO", each if [STOCK CODE] ="BUYERNO " then [No] else null),
    FilledDown = Table.FillDown(AddedBuyer,{"OUTLET CODE", "BUYER NO"}),
    FilteredRows = Table.SelectRows(FilledDown, each ([STOCK ITEM] <> null)),
    SelectColumns = Table.SelectColumns(FilteredRows,{"OUTLET CODE", "BUYER NO", "STOCK CODE", "STOCK ITEM", "QTY"})
in
    SelectColumns

STOCK CODE is Text, change type to Number if need.