Combining row data for matching ID - help!

let
Source = Csv.Document(File.Contents("D:\Dropbox\Oscar Properties\Land Registry Price Data\Downloads\pp-complete.txt"),[Delimiter=",", Columns=16, Encoding=1252, QuoteStyle=QuoteStyle.None]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Column1", type text}, {"Column2", Int64.Type}, {"Column3", type datetime}, {"Column4", type text}, {"Column5", type text}, {"Column6", type text}, {"Column7", type text}, {"Column8", type text}, {"Column9", type text}, {"Column10", type text}, {"Column11", type text}, {"Column12", type text}, {"Column13", type text}, {"Column14", type text}, {"Column15", type text}, {"Column16", type text}}),
#"Removed Columns" = Table.RemoveColumns(#"Changed Type",{"Column1"}),
#"Renamed Columns" = Table.RenameColumns(#"Removed Columns",{{"Column2", "Price"}, {"Column3", "Date"}}),
#"Reordered Columns" = Table.ReorderColumns(#"Renamed Columns",{"Date", "Price", "Column4", "Column5", "Column6", "Column7", "Column8", "Column9", "Column10", "Column11", "Column12", "Column13", "Column14", "Column15", "Column16"}),
#"Renamed Columns1" = Table.RenameColumns(#"Reordered Columns",{{"Column5", "Type"}}),
#"Filtered Rows" = Table.SelectRows(#"Renamed Columns1", each [Column4] <> null and [Column4] <> ""),
#"Merged Columns" = Table.CombineColumns(#"Filtered Rows",{"Column4", "Column8", "Column9"},Combiner.CombineTextByDelimiter("", QuoteStyle.None),"ID"),
#"Reordered Columns1" = Table.ReorderColumns(#"Merged Columns",{"ID", "Date", "Price", "Type", "Column6", "Column7", "Column10", "Column11", "Column12", "Column13", "Column14", "Column15", "Column16"}),
#"Removed Columns1" = Table.RemoveColumns(#"Reordered Columns1",{"Column6", "Column7", "Column10", "Column11", "Column12", "Column13", "Column14", "Column15", "Column16"}),
#"Sorted Rows" = Table.Sort(#"Removed Columns1",{{"ID", Order.Ascending}}),
#"Filtered Rows1" = Table.SelectRows(#"Sorted Rows", each [Date] >= #datetime(2010, 1, 1, 0, 0, 0)),
#"Filtered Rows2" = Table.SelectRows(#"Filtered Rows1", each true),
#"Filtered Rows3" = Table.SelectRows(#"Filtered Rows2", each Text.StartsWith([ID], "AL1 ")),
Group = Table.Group(#"Filtered Rows3", {"ID"}, {{"All", each Table.Sort(_, {"Date", 0})}}),
Filter = Table.SelectRows(Group,each Table.RowCount([All])>1),
dp = {"Date","Price"},
dpt = dp & {"Type"},
RcdCol = Table.AddColumn(Filter, "Record", each Record.SelectFields(Table.First([All]),dp)),
RcdCol1 = Table.AddColumn(RcdCol, "Record1", each Record.SelectFields(Table.Last([All]),dpt)),
RemoveColumn = Table.RemoveColumns(RcdCol1,{"All"}),
ExpandCol = Table.ExpandRecordColumn(RemoveColumn, "Record", dp, {"Date1", "Price1"}),
Result = Table.ExpandRecordColumn(ExpandCol, "Record1", dpt, {"Date2", "Price2", "Type"})
in
Result